Birthstones by Month and Gems for Zodiac Signs

Image showing birthstones by months

For a long, the idea of wearing a person wearing a birthstone that corresponds to a  birth month had always been appealing. These birthstones are gemstones worn to denote the month of a person’s birth. While some select their stones based on the calendar month of birth, some of the stones could also be selected based on the zodiac period of the person’s birth.

The idea of wearing these special gems is quite old. Then, it was widely believed that it provided its wearers with good health, good luck and could wade off evil spirits. While some people wore it daily, many wore it on special occasions for special favors. It was not uncommon also to have people wear it on their journeys as a token for protection or when presented with a great opportunity as a token for excellence.

Today, some people still hold on to part of these beliefs. Those who do, wear them as statement pieces or pieces of jewelry. The most common style is to have the specific stone forming the main pendant in necklaces or rings. The colors of these stones are also used as dressing themes if it is not possible to get the stone itself. 

Because of the high economic value attached to these gems and their beautiful colors, they make amazing gift ideas for those who can afford them. Apart from wearing the stones on your body, you could choose to include them as part of your home decoration. Some of these stones are also attributed to healing powers making them treasured.

Many of the gemstones are minerals that are naturally occurring, with a defined crystalline structure, and specific chemistry. Some, however, are not classified as minerals as they do not meet this requirement. An example being pearl.

Table of Contents

Birthstones by month

Every month has a unique birthstone or set of birthstones. Each of these gemstones is thought to represent specific things and is symbolic of their months.

Garnet: January birthstone

Garnet, the birthstone for January
Garnet Source: Vitale 1913

The birthstone for January is Garnet. Its name comes from the Latin word granatum for its deep red color. It was likened to the seeds of a pomegranate that also occurs in deep shades of red. In olden times, it was believed that garnets could wade off accidents from travelers when they are away from home.

Description and Properties of Birthstone for January

Garnet belongs to the silicate mineral groups. Garnets come in several colors. Some of them could be orange and some green. Many garnets however are seen as a rich shade of red.

Garnets with different colors have been given different names although they all belong to the garnet family. For instance, the common red garnet is called pyrope whereas a garnet that displays a yellow color is known as spessartine. The different shades that accompany individual garnet occurrences can be due to the characteristic cation in the silicate structure.

Chemical composition: X3Y2(SiO4)3 with X and Y denoting different elements that give rise to several varieties of garnets. 

Crystallography: Garnet has its crystals arranged in the isometric system.

Hardness: 6.5 – 7.5

Geologic importance

Garnet is a metamorphic mineral hence finding it in any rock indicates that the rock is a metamorphic rock. The red garnets are the commonest types found and are often seen in kimberlites, peridotites, and serpentines

Areas of most occurrence of January Birthstone

Most of the garnet deposits can be found in the USA, Australia, South Africa, China, India, Canada, Pakistan, Ukraine, Chile, Czech Republic, Spain, and Thailand.

Other uses 

  • Garnets have been used as gemstones from years back till date.
  • They can be crushed and used as abrasives making an excellent replacement to the commonly used silica sands.

Amethyst, the birthstone for February

Amethyst, the birthstone for February
Amethyst Gemstone for February

The birthstone for February is Amethyst. This gem comes in a vivid purple color that makes it the most famous purple gemstone. 

In myths, wearers of amethyst do so to keep a clear head. It is thought to remove the intoxicating effects of Dionysius or Bacchus (the Greek and Roman god of wine). 

Description of Birthstone for February

Amethyst is a variant of the mineral quartz. It occurs in varied shades of purple with some so light that the color is barely seen or others so dark that the amethyst appears opaque. Quartz is known to be clear or almost clear. The colors exhibited by amethyst are caused by impurities of iron, transition metals, trace metals, or irradiation.

Chemical composition: (SiO2) the presence of little quantities of trace metals give amethyst its color.

Crystallography: Amethyst displays a trigonal arrangement of its crystals.

Hardness: it has a hardness of 7 although this could vary depending on the variety.

Geologic importance

Amethysts can be found in both igneous and metamorphic rocks. They are formed in cavities called geodes present in rocks. These cavities are created as volcanic rock forms. Hot air and mineral-rich water that are components of the magma begin to distill from the rock into the cavities or spaces in the rock. As the hot fluid cools, the minerals dissolved in the fluids begin to crystallize and grow in space.

Areas of most occurrence

Amethysts are found in many regions of Africa and South America. Countries such as Brazil, Uruguay, Zambia, South Africa, South Korea, Mexico, Russia, and the USA have occurrences of this gemstone.

Other uses of amethyst – the gemstone for February

  • The major use of this stone is in jewelry. Since it is a type of quartz, its hardness makes it very resistant to scratches and reactions.
  • Some cultures believe in its powers as a panacea to stress and to aid meditations. Hence has been a form of medication.

Aquamarine, the Birthstone for March

Aquamarine, the birthstone for March
Aquamarine Source: Indiamart

The birthstone for March is aquamarine. Named so because of its sea-like color, aquamarine is used as the birthstone for March. This gem comes in a blue or bluish-green color similar to that of the sea. Many sailors wore it or had it with them when going on voyages because it was believed to calm the sea.

Many more stories of aquamarine exist from old. For instance, it is believed to embody eternal life as it bears similar color to both the sky and the sea. It was also a special gift for married couples as it is believed to promote fertility.


Aquamarine is beryl. They are cyclosilicates composed mainly of aluminum and beryllium. These are known for their beautiful colors and large crystals. The presence of iron (ii) ions in the structure of the mineral gives the beryl (aquamarine) its pale blue color.

It should be noted that the color of the aquamarine varies from pale blue to a deep rich shade. Nevertheless, the deeper shades of this gem are more desirable. Thus, the deeper the color of the aquamarine, the more the price it commands in the market. 

Chemical composition: Be3Al2(Si6O18). Fe2+ or Fe3+ present in trace quantity would give the beryl a cyan to a bluish color.

Crystallography: The crystals of aquamarine are arranged in a hexagonal system.

Hardness: 7.5 – 8

Geologic importance

As with many gems, aquamarine is formed under the earth by magma. They are often found in host rocks called pegmatites. Pegmatites are igneous rocks too but are formed under conditions that allow the crystal grains to grow and become big. They are often formed in the last stages of magma crystallization.

It is also possible to find some aquamarine in granites and some metamorphic rocks mineralized through hydrothermal processes. When these rocks become weathered, the gem in them becomes exposed and because of the hardness of the aquamarine, it remains undisturbed. When found in stream sediment, it was probably washed downstream from a source not too far upstream.

Areas of most occurrence of March gemstone

Countries such as the USA, Brazil, Madagascar, Zambia, Colombia, Tanzania, and Kenya are places aquamarine can be found.


  • The hardness of the mineral makes it resistant to abrasion. This is an important characteristic of a gemstone.
  • Some spirituals believe the stone possesses healing powers, the ability to boost confidence as well as creating a balanced mindset.

Diamond, the birthstone for April

Diamond, the birthstone for April
Diamond Source: Alrosa PJSC

The classy diamond is the birthstone for April. Like many gems, the diamond was named by ancient Greeks based on its pure look and indestructible nature. It is believed that it was first discovered in India about 6,000 years ago. For a long time, India was believed to be the only place this gem could be got. However, a little amount was found in Brazil in 1725. 

Towards the last half of the 1800s, deposits of this incredible gem were found along the Orange River and places in Southern Africa. More diamond mines were also established later in some parts of Russia.

The spike in the number being mined brought down its value a bit. Howbeit, they remain one of the dearest gems on earth as it remains not just a birthstone but a symbol of a life-long commitment.

Description of April Birthstone

Diamond is composed of natural carbon as the only element in its chemistry. It is very similar to coal in its composition except of course for its colors. Diamonds come in colors that could range from yellow, pink, and brown to colorless. 

The colorless and transparent diamonds have earned more respect as a fitting description for what this gem looks like especially by jewelers.  When these colors occur, it is often due to the presence of trace impurities such as boron, nitrogen, or dirty. Colored diamonds in deep shades of red, orange, blue, purple, pink, and green are rare but command very high prices.

Chemical composition: (C)

Crystallography: Diamond crystals are arranged in the cubic system.

Hardness: With a hardness of 10, diamond is known to have the highest hardness of all known natural minerals. 

Geologic importance

The majority of diamonds on the earth are formed under intense temperature and pressure conditions in the mantle. Although, some found in the crust are metamorphic products of buried rocks with the crust.

Because of the high carbon content prevalent in them, some people conclude that they were formed from coal. However, only a very small percentage of diamonds are formed by the high compression of coal beds. Some extra-terrestrial diamonds are also deposited on the earth through meteorites. Unfortunately, these do not occur in quantities that can be mined.

Most of the diamonds on earth are found in a type of rock known as kimberlites. These often occur as pipes within rocks or in dikes and sills. There are two other diamond-bearing rocks; lamprophyres and lamproites.

Areas of most occurrence of April gemstone

Areas, where diamonds have been noted to occur, include Russia, Botswana, South Africa, Australia, and Canada. A small amount is found in Brazil, China, the USA, and India.


  • The most common use of diamonds is in making jewelry. Their characteristic hardness makes them durable gemstones
  • Many industrial abrasives and some drill bits are made from diamonds.
  • Its high reflective property makes it to be used in making lenses.

Emerald: the birthstone for May

Emerald, the birthstone for May
Emerald – the gemstone for the month of May

The birthstone for May is the green emerald. Emerald here has Persian history! It was originally named by them based on its green color. Much later, the name was changed to Greek and Latin at different times. 

Outside Persia, mining for emeralds began a long time. Some hold that it began in ancient Egypt. It was believed the Cleopatra mines that were rediscovered in 1818 produced a certain amount of emerald. The queen was passionate about the stone, including it in her jewels and adornments. However, due to the low quality and small quantity of the gem discovered there, the mines were abandoned.

Emerald was commonly used by the nobles and royalties of the Roman Empire. It was revered by the Incas and Aztecs of South America. It was passionately protected by Shah Jahan of India. This green gem adorns several rings, crowns, and power signets. It was the object of discourse and strive in the 16th Century looting of the New World by Spanish Explorers. This gemstone has had a long history that makes it treasured by royalties and the wealthy.

The stone is worn as a token of wisdom, love, and protection. It is also believed to open up a person’s senses of spiritual awareness leading such to a strengthened relationship with the divine. The powerful green color associated with this birthstone holds a symbol of life, creation, and development.

Description of Birthstone for May

Emerald has a deep rich green color. This gem belonging to the beryl family has this green tint when impurities of chromium or vanadium are present in trace amounts. Inclusions and sub-surface fractures are features very common to the mineral. Undoubtedly, it is very rare to find emeralds that occur without these inclusions.

Because of this known feature of the emeralds, many jewelers take special care to improve their qualities before they are sold. Various colorless oils, waxes, and polymers the most common being cedar oil. 

Because of this oil treatment, cleaning of emeralds through heating methods is often not advisable. As the heat can melt out the oil making the gemstone.

Emerald is one of the rarest gemstones on earth. It belongs to the group of big four minerals which includes the rarest gems on earth. Other members of the group are diamonds, rubies, and sapphire.

Chemical composition: Be3Al2(SiO3)6

Crystallography: Hexagonal

Hardness: 7.5-8

Geologic importance

This is one of the gemstones that can be found in several rock types (igneous, sedimentary, and metamorphic). However, most of the world’s emerald deposits were found in areas of contact metamorphism. This could be an area between granitic magma and another rock rich in chromium or vanadium. These host rocks could be of igneous origins or their shale derivatives.

It is also possible for emeralds to be deposited along faults and fractures present in sedimentary rocks. This deposition could be a result of beryllium-bearing brines moving up chromium or vanadium-rich sedimentary rocks. This process accounts for most of the gem-quality emeralds around.

Also, emeralds could form at the margins of pegmatite where metasomatic fluids interact with the beryllium in the pegmatite. Notwithstanding their seeming versatile occurrence, it is not common for emerald to be mined from alluvial deposits. 

Consequently, what is important is that there is the presence of chromium and vanadium in the rock. When beryl forms, it is usually colorless, the minerals chromium and vanadium add the green color that makes emeralds different from other beryl minerals.

Areas of most occurrence of May Gemstone

Despite its rarity, emerald is found on five continents with Brazil, Colombia, Zambia, Madagascar, and Russia being the largest producers. Other countries where emeralds are found include Afghanistan, Pakistan, and India. 

For most of the areas, they are found in the Precambrian rocks. Some are also found in younger volcano-sedimentary series.

Other uses 

  • The major use of this stone is in jewelry. They are very rare to come by so are used mainly by the rich, wealthy, or royalty.
  • It also has astrological uses. 

Birthstones for June: Pearl, Moonstone, and Alexandrite 

June is one of the months with more than one birthstone. These arise from the different stones on the traditional and modern list for birthstones. In June’s case, it has three stones.

Pearl, the birthstone for June
Pearl – one of the gemstones for June

Pearls are gems from living organisms and the only birthstone from an animal source. They are found within mollusks of both salt and fresh water habitats. Their occurrence in nature is quite rare necessitating their cultivation by humans. It could come in white, pink to grey colors. For the wearer, the cool colors of the pearl convey a representation of purity and integrity. 

Moonstone, the second birthstone for June
Moonstone – one of the gemstones for June

Moonstone is one of the not-so-famous gem minerals. It comes with a smoky, pearly, and opalescence appearance. The name was derived from its appearance that is similar to a moon. As far back as during the ancient Roman periods, it was worn as a jewel. It was believed it was made from the rays of the moon that later became solidified and it was associated with the moon deities. The choice of moonstone carries a representation of feminine energy and serves as a source of inspiration.

Alexandrite, the third birthstone for June
Alexandrite – one of the gemstones for June

Alexandrite on the other hand occurs on the modern list as the gem for June. One remarkable feature of this stone is its change of colors under different lighting conditions. In sunlight, alexandrite appears green but looks red in incandescent light. 

Discovered in Russia in the 19th century, this gem is extremely rare and believed to bring good luck to its wearer. The stone was named after Czar Alexander II.

One would expect that the change from pearls and moonstone to alexandrite as the modern birthstone for June should push this gem forward. Howbeit, alexandrite is even rarer than pearl and many have not even seen it. Therefore pearl jewelry continues to be bought as the birthstone for June.

Description of June Birthstones

Pearl: (CaCO3)

Pearls come in different shapes. Some could be small with shapes as rice, rounded, pear-shaped, or even irregular. Most pearls are white or cream-colored. Some pearls come in green, blue, brown, or black. 

Pearls generally have an iridescence appearance from reflections off the layers of calcite that make it up.

Moonstone: (Na,K)Al(Si3O8)

Moonstone is an aluminosilicate with the metals sodium and potassium. Specifically, it is an orthoclase feldspar and could also be called hecatolite.

This opaque silicate belongs to the family of the feldspars. It comes with an adularescence as a result of the reflection of light over the layers of cabochon in the mineral. Just like a pearl with a low hardness value, it is a very delicate gem thus not suitable for everyday wearing. 

This beautiful gem comes in different colors from blue, green, and pink to a rainbow-looking variety. There are colorless varieties as well.

Alexandrite: (Cr3+)(BeAL2O4)

Alexandrite is one of the few stones that are rarer than diamonds. The presence of chromium gives this stone the ability to change color. It could appear like an emerald in bright light and have the appearance of a ruby in dim light. 

It belongs to a group of minerals known as chrysoberyl. This is made up mainly of the elements aluminum and beryllium. However, in alexandrites, some aluminum is replaced by chromium which causes it to appear red in the dark. Some alexandrites appear yellow or pink in daylight and red in dark spaces. 

Crystallography: Crystallography of pearl is orthorhombic, that of moonstone is monoclinic while alexandrite also crystallizes in the orthorhombic system.

Hardness: The hardness of pearl ranges from 2.5 to 4.5 and Moonstone has a hardness of 6. Alexandrite on the other hand has a higher value on the Mohs scale with a value of 8

Geologic importance of June birthstones

Pearls are hard glistening gems produced in the shells of mollusks and conulariids. When an irritant sneaks into the shells of these organisms, it secretes a fluid to serve as protection. This fluid covers the contaminant and over time solidifies to form hear pearls in the shell. They could be found attached directly to the inner surface of the mollusk shells. Such types are known as blister pearls.

Moonstones are formed from the separation of feldspars. As the magma rises and its constituent minerals form, the two types of feldspar form together. As the minerals cool, they are separated into alternate layers. This accounts for the unique reflection akin to the moonstone.

The formation of alexandrite depends on very peculiar conditions. As a chrysoberyl, there must be beryllium and aluminum. Howbeit, for the chrysoberyl to be an alexandrite, there must also be trace metals such as chromium, iron, vanadium, and titanium. 

This gem occurs mostly in a metamorphic rock. The slim chances that you would ever have beryllium and aluminum occurring with chromium are what lends the gem its rarity. Its uniqueness arises also from the surprising absence of silica from the mix. This would have resulted in the formation of an emerald.

Areas of most occurrence

The Persian Gulf is known to have the finest saltwater pearls in the world. This area is also regarded as having a large amount of it. Pearls are also found on the coasts of Japan, Australia, India, Central America, and some rivers in Europe. A large number of cultivated saltwater pearls are cultivated in Japan while freshwater pearls are common in China.

Sri Lanka is the country home of moonstone. There are other specimens from India, the USA, Brazil, Australia, and Madagascar.

The gem alexandrite was first discovered in the Ural Mountains in Russia. While it remains one of the rarest gems on earth, other places it has been found include; Sri Lanka, Brazil, and parts of East Africa.

Other uses 

  • Pearls are crushed and used as components in making some cosmetics
  • Inferior pearls have found other uses in medicines when crushed.
  • To date, moonstone is worn by many as a panacea to several spiritual and health problems.
  • Alexandrite is also used for crystal healing.

Ruby, the birthstone for July

Ruby, the birthstone for July

July’s birthstone ruby is also known as the red gem. This precious stone was treasured amongst others for its rarity and hardness. It is one of the rarest gems on earth earning it a spot amongst the big four. Although they are opaque, they are still valuable. 

Rubies were mentioned many times in the Bible as with several other stones. They were greatly regarded amongst many cultures such as the Hindus and in several Asian countries. 

Its strong red color is believed to be associated with life force, energy, and youthfulness. Many warriors in those periods wore it as a token for protection. Rubies are common royal jewels and used by them as a promise of health and wisdom.

The rarity of rubies earned them the Indian title of “Ratnaraj” which translates to “king of precious stones”. There are also rubies amongst the British crown jewels. 


Rubies come in red colors. This could range from a pinkish shade, orange, to blood-red colors. All shades of rubies are valuable however those with a deep red hue and a slight shade of purple are the most sought after. Rubies with this description are called pigeon’s blood.

Despite their difference in colors, rubies and sapphire both are types of corundum. They have the same chemical formula (except of course the addition of the element that gives each its distinct color). Corundum could occur as colorless minerals, however, the presence of chromium as it forms produces the ruby. The amount of chromium in the gem determines how deep the red hue would be.

Rubies also go through preparation to make them gem-worthy. For instance, they could be heated under controlled conditions to remove inclusions and intensify their colors and improve clarity.

For cases when the ruby might have fractures, as is common to natural ones, they can be filled with oils, waxes, or resins. They could also be filled with glass, a small amount of flux, or more durable materials. These are done without affecting the clarity of the gem. 

Chemical composition: Cr (Al2O3)

Crystallography: ruby as a species of corundum has its crystals arranged in the trigonal system.

Hardness: Corundum is the second hardest mineral after diamond explaining the hardness of ruby as 9 on the scale of hardness.

Geologic importance

Corundum is formed in areas below the earth’s surface with high temperature and pressure conditions. It is essentially composed of oxides of aluminum. Often this mineral is colorless but when part of its aluminum is replaced with trace minerals such as chromium, you have ruby. 

They are found mainly in igneous and metamorphic rocks. However, it is difficult to mine gems from a hard rock so these are rarely mined from the rocks in which they were formed. When their parent rocks are weathered, erosion moves them away into streams. This way, most of the rubies mined are from stream sediments.

Areas of most occurrence

Rubies are closely associated with Asian countries especially in the lands close to the Himalayans. Myanmar, India, Pakistan, Thailand, and Nepal are major sources of rubies. Other countries where rubies have been found are the USA, Brazil, Tanzania, Australia, Madagascar, and Colombia. 

Other uses 

  • Rubies along with other gemstones are used in making bearings in wristwatches.
  • Rubies are also used in ruby lasers, a common example being ruby laser pointers.

Peridot; birthstone for August

Peridot, the birthstone for AUgust

Peridot is the birthstone for August. The cool yellowish-green color of peridot brings peace, health, and rest to the mind and body. Its name comes from the Arabic word “faridat” meaning gem. For over 4,000 years, the ancient Egyptians adored the gem peridot. It was thought to be a gem from the sun and was even named the “evening emerald” for its dark green appearance in dim light. 

They were prominent in the palace and adorned the shrines of the Three Holy Kings Cologne Cathedral in Germany. These stones were thought to be emeralds at that time. It was confused with several gems at that time. Some even named it topaz.

Wearing peridot is believed to protect the wearer from night terrors and evil spirits.


Peridot is sometimes called chrysolite. This is also a silicate mineral and more specifically, olivine. Magnesium is very abundant in this variety of olivine. 

Peridot is one of the few minerals that come in a single color. Every peridot comes in a green color although the intensity of the green depends entirely on the abundance of iron in it.

As with many naturally occurring gems, peridot also has inclusions. In some instances, there are inclusions of chromite, biotite, spinel, or other fluid in the peridot. 

Chemical Formula: (MgFe)2SiO4

Crystallography: Orthorhombic

Hardness: 6.5 to 7

Geologic Importance of August Birthstone

Peridot is one of the two minerals that are formed in the upper mantle, the other being diamond. Once these are formed at such great depths, they are brought up in magmas. Peridot as with the mineral olivine is brought to the earth’s surface by silica deficient rocks. These are mainly the mafic and ultramafic rocks of the mantle.

Although olivine is abundant, finding gem-quality peridot is difficult. The rarity of peridot hinges on the fact that they are easily weathered once they arrive at the earth’s surface.

Peridot crystals have also been observed in meteorites. The most common being the Fukang meteorite in China.

Areas of most occurrence

Peridots were first discovered and mined in Egypt and their source was a well-kept secret. Today, peridot mines have been sited in Hawaii, the USA, Myanmar, Pakistan, and areas within and around the Himalayans. It has also been discovered in Brazil, China, Kenya, South Africa, Sri Lanka, Tanzania, and Mexico.

Other uses 

  • Apart from its common use in jewelry making, low-grade peridots are used as refractory sands
  • Some are also used as abrasives.
  • It has also been selected as able to open up the chakras thereby clearing emotional stress, depression and bringing balance to the mind.

September birthstone: Sapphire

Sapphire, the birthstone for September

The birthstone for September is the blue corundum called sapphire. It has had a long history that spanned as long as the Middle Ages. It was used across cultures by the Hebrews, Greeks, and India.

Sapphire was a common jewel for royalties as they believed it protected them from envy and harm. Its blue charm is believed to reveal secrets of oracles, bring peace with enemies and guard chastity. It was also common to find clergymen wearing the gem as a symbol of heaven.

In 1981, Britain’s Prince Charles gave a sapphire ring to Princess Diana on their engagement. This act of love has brought sapphire higher in its use as a romantic jewel. Much later in 2010, Prince Williams proposed to Kate Middleton with this sapphire ring.

Description of Birthstone for September

As corundum, sapphires have similar characteristics and chemistry as the ruby. The difference here arises from the presence of iron in the sapphire and the abundance of chromium in rubies. 

Sapphires are commonly blue in several shades. This variety of sapphire is the most sought after and is the most expensive. Rich blue sapphires with vivid saturation cost more. 

Sapphires that come in other colors are known as “fancy sapphire” These could come in yellow, orange, brown, violet, purple, or green. Orange sapphires which are the highest priced non-blue types are called “Padparadscha”.  

There are also sapphires with multi colors and those with amazing physical attributes. Notwithstanding their beauty, natural sapphires contain inclusions and are treated not so differently from corundum.

Chemical formula: (Al2O3)

Crystallography: Titanium (Ti) or iron (Fe) gives the corundum the blue color that makes it a sapphire 

Hardness: 9

Geologic importance

In some scenarios, sapphires and rubies occur together. Corundum as a mineral is formed in the depths of the earth. It is however brought to the earth’s surface through magmatic activities. It should be noted that these are found in special kinds of magma that do not contain free quartz and high aluminum content. They are thus called silica deficient an example is basalt. 

Whereas these gems can be found in metamorphic rocks especially zones of contact metamorphism economic quantities of these gems are recovered in sedimentary deposits. It is more expensive to recover sapphire (and any gemstone) from hard rock except when they weather away. Weathering causes most of the other portions of the rocks to be removed leaving behind the more resistant minerals concentrated in a place.

Areas of most occurrence

Sapphires are the second most common gemstone and the most common colored gemstone. Major significant sapphire deposits in the world include; China, Myanmar, Madagascar, Nigeria, Kenya. Other places are Australia, Afghanistan, the USA, Cameroon, and Thailand. Sri Lanka is also well known for its sapphires especially the padparadscha.

Other uses 

  • Sapphires are used as wristwatch crystals, windows, and as components in infrared opticals.

Tourmaline and Opal: the birthstones for October

Just as the case with June, October is also bestowed with two birthstones. These are tourmaline and opal. While tourmaline is the new addition to the list one striking feature of both stones is their rich display of colors. 

Opal, the birthstone for October

Opal Gemstone for October

Opals have been priced also for a long time in history. Opal artifacts dated to about 4000B.C. were found in a cave in Kenya. The given name however has Indian history and was recognized by the Greeks for its color-changing ability. History is replete with how they were used as gifts or symbols.

Tourmaline, the second birthstone for October
Rainbow tourmaline Source: Geologypage

Tourmaline Gemstone for October

Tourmaline was named for its many colors. In ancient times, it was believed that tourmaline could inspire an artist. Each color of tourmaline is believed to come with its unique healing powers. For example, pink tourmaline is believed to be associated with love and gentleness while green infuses the wearer with strength and courage. 


Opals can be treated with oils, wax, or even plastics to improve their qualities and fill fractures. Therefore, the easiest way to clean or maintain the gem is by using warm soapy water. Some of the common colors associated with opals are white, yellow, red, and orange. These could however come in various shades depending on how much light diffraction the gem displays.

Tourmaline is a cyclosilicate with boron in its structure. Tourmaline wears the badge for being the gem that comes in a variety of colors ranging from black, colorless, to different hues from the rainbow. Also, some tourmaline could have multi colors in a single stone. The rich colors associated with this gem arise from the presence of trace-specific trace elements in each variety. This has caused it to be mistaken for other types. 

Chemical formula: Opal is has a silicate with water in its structure (SiO2).nH2O3. Tourmaline on the other hand is a bit complex with a chemical formula XY3Z6B3Si6(O,OH)30(OH,F). 

Depending on the variety, X could be elements, sodium, calcium, or both. Y could be aluminum, lithium, magnesium, iron (ii) or iron (iii), and manganese. Z could be aluminum, chromium, magnesium, or iron (iii). Boron is a staple and there could oxygen or hydroxyl or both. It could also have fluorine in its chemistry. 

Crystallography: Opal is an amorphous solid meaning it does not have a structured arrangement. On the other hand, tourmaline is a well-structured cyclosilicate having its crystals arranged in the hexagonal system.

Hardness: Opal has a hardness of between 5 and 6.5 on the Moh’s hardness scale while tourmaline has a value between 7 and 7.5

Geologic importance

Opal is formed when silica-rich solutions in the earth settle under gravity. Often, this occurs when running underground water dissolves silica especially from sandstone or clay sediments and deposits them in cracks or voids. When the water in these solutions gets evaporated, it leaves behind silica deposits in these spaces. 

Different types of opal from different parts of the world have been identified with specific characteristics.

Tourmaline is essentially an igneous mineral and found in pegmatites. It could also be found in metamorphic rocks such as schists and marble. Minor quantities of tourmaline can be found in placer deposits.

Areas of most occurrence

Australia accounts for most of the opals in the world. Opals are also found in Ethiopia, Brazil, Mexico, Indonesia, Madagascar, Turkey, Peru, and the USA.

Tourmaline is found in Brazil, Afghanistan, Pakistan, Madagascar, the USA, and Mozambique. Nigeria, Namibia, Sri Lanka, Tanzania are areas where tourmaline can be found both in gem quality and as a specimen.

Other uses 

  • Tourmaline is worn to boost self-confidence, create inspiration, and reduce stress. 
  • Internally flawless tourmaline are well sought after by electrical companies in piezoelectric components.
  • Opals have also found industrial uses as insulators, fillers, abrasives, and important components in ceramic making.

November birthstones: Topaz and Citrine

Topaz and citrine are the two birthstones for November. Both stones are chosen for their calming auras 


Topaz, the birthstone for November
Topaz Gemstone 

Topaz is believed to have been named “tapaz” the old Sanskrit word for fire. This is because it was believed that all topaz comes with a golden color. It was not until much later did they discover that many of the stones wrongly labeled as topaz were in fact citrine.

Topaz was worn by the monarchs of ancient times as it was believed to change color if the food or drink presented was poisoned. It was closely linked to the sun deity by both the Egyptians and the Romans and was believed to embody the energy and strength of the sun.

Citrine, the second birthstone for November

Citrine on the other hand had always been a rare gem. It is difficult to find naturally occurring citrine. In ancient times, it was believed to protect from snake bites and cure liver, heart, and digestive problems.


Pure topaz comes as a colorless stone. The presence of other elements as impurities, while it is formed, gives it different colors. Most of the blue topaz sold in the market are formed from heat irradiation of pale species.

Citrine belongs to the silicate family. In fact, it is a variety of the mineral quartz. Although the cause of the coloration of this variety of quartz is not yet certain, speculations are on aluminum and irradiation. 

This rare quartz species comes in a light to pale yellow color. The shades of yellow range from yellowish orange to a hint of brown or red.

Chemical Formula: chemical formula of topaz is Al2SiO4(F,OH)2 while the chemical formula of citrine is SiO2

Crystallography: topaz has an orthorhombic crystal system and citrine has its crystals arranged in the trigonal system. 

Hardness: Topaz has a hardness of 8 while citrine a hardness of 7.

Geologic importance

Topaz are formed in spaces within igneous rocks and cavities in pegmatites. As the magma flows it dissolves in its fluorine from the surroundings. Ultimately as the magma cools, minerals are sorted and crystallize from it. In these magmatic mixtures, it is usually one of the last minerals to crystallize. Upon weathering and transportation, they can be found in sedimentary deposits.

Citrine is formed naturally as a variant of quartz. Some citrine are colored by the presence of aluminum or coatings of iron oxide in them. Most of the citrine found are believed to be formed by the irradiation of smoky quartz or amethyst. This is backed by the appearance of smoky features in some citrines. 

However clear distinctions can be drawn between heated amethysts and citrine. 

Areas of most occurrence

Topaz can be found in Brazil, Sri Lanka, Italy, Russia, Nigeria, the USA, Sweden, Afghanistan, Japan, Mexico, and Australia. It is also possible to collect gem-quality citrine from Brazil, Russia, Colombia, Congo, Madagascar, Spain, and South Africa.

Other uses 

  • Apart from its use as a gemstone, topaz has been used in refractories as well as in glass and ceramic making companies.
  • Citrine is used mainly as a gemstone and for its metaphysical powers.

Zircon, Turquoise, and Tanzanite; Birthstones for December

People whose birthday is in December have the wide option of stones to choose from. This month is bequeathed with three stones, zircon, turquoise, and tanzanite.

Blue zircon is also a birthstone for December
Blue Zircon (Source:

Zircon comes in multiple colors however, your blue zircon was the gem of choice for the last month of the year. This gem is believed to provide protection and knowledge and induce sleep. The blue color of this gem for centuries was believed to be symbolic of the heavens.

Turquoise, the birthstone for December
Turquoise  (Source: Geologypage)

Similarly, turquoise as with many gemstone recovery activities was also prevalent in ancient Egypt. They mined it for the belief that it brought joy. Persians also favored the use of this gem by naming it “pirouzeh” which means victory. Turkish traders brought this Persian treasure to Europe around the 13th century where it earned its name Turquoise from the French word that implied the “Turkish Stone”.

Tanzanite, the second birthstone for December
Tanzanite Source:

Tanzanite is an equally enchanting blue gem and is one of the rarest gems on earth. This rare blue gem is said to be 1000 times rarer than a diamond. It was initially sought out as a substitute for sapphire. The largest tanzanite stones ever recovered were unearthed in 2020 and they weighed 20.4 and 11.2 pounds respectively.


Zircon Gemstone for December (ZrSiO4)

The most common color for the mineral zircon is brownish-red. However, the presence of impurities gives the different varieties their specific colors. No doubt, the blue zircon is the most desirable.

Often, these colors are from the presence of radioactive minerals such as thorium and uranium. The zircon is thus irradiated to both lessen the radioactive effect and to improve its appearance. Because of their hardness, they are among the oldest minerals on earth with Australian zircons from Jack Hill dating to about 4.4 billion years.

Turquoise Gemstone for December, CuAl6(PO4)4(OH)8.4H2O:

Turquoise is a hydrated phosphate mineral that contains copper and aluminum. These give the gem the peculiar blue to the bluish-green color associated with it. As common to many opaque gems, there have been imitations made in the lab. Consequently, this has lowered the value for turquoise despite its rarity.

With a hardness similar to that of glass, turquoise is quite fragile. Therefore to enhance its color, hardness, and reduce its porosity it is often treated. These treatments could be through heat or fillings using wax, plastics, or oils.

Tanzanite Gemstone for December, (Ca2Al3SiO4)(Si2O7)O(OH)+(Cr,Sr)

The three color angle of the tanzanite is another advantage of this December gem. Depending on the angle and the light under which it is viewed, it gives off about three different colors. Under sunlight or bright light, it appears blue. When viewed under incandescent light, it appears purplish with red flashes within it.

Crystallography: Tetragonal system for zircon, a triclinic system for turquoise, and orthorhombic system for tanzanite.

Hardness: Zircon, turquoise, and tanzanite have a hardness of 6 – 7.5, 6, and 6.5 respectively on the Mohs scale of hardness.

Geologic importance

Zircon is found as a common accessory mineral in many igneous and metamorphic rocks. The intense heat in volcanic or metamorphic activities is required in the formation of zircon. It is possible to see sedimentary rocks that contain detrital grains of zircon. However, zircons of economic importance are found mostly in pegmatites, heavy mineral sand deposits, and rarely in alkaline rocks.

Turquoise is found mainly in arid areas where the soils are rich in copper, fillings, cavities, and fractures in rocks. It forms as a secondary mineral from weathering and oxidation processes. Essentially, the copper can be got from primary copper sulfides, or carbonates, phosphates from apatite while aluminum from feldspars.

When these acidic solutions begin to percolate, turquoise begins to grow out. Many of the turquoise deposits are seen as nodules, stalactites, intergrowths, or replacing other materials such as fossils. The gem itself is found most time in a cryptocrystalline state.

Tanzanite is found only in a place. It can be deduced that it was formed from the intense heat from the activities of plate movements that created Mount Kilimajaro. The geology of the area as a whole is complex with several structures together. Deposits of tanzanite are found in the hinges of isoclinal folds.

Areas of most occurrence

Zircon can be found in areas such as Sri Lanka, Cambodia, Canada, Myanmar, Australia, and Thailand. Similarly, the world’s largest producer of turquoise is the USA. Other areas where it can be found include Egypt, Iran, Bulgaria, China, Australia, and India. Tanzanite on the other hand is exclusive and found only in areas around Mount Kilimanjaro in Tanzania.

Other Uses of December Gemstones

  • Zircon is popularly used in foundries and ceramics companies.
  • Zircon is also used in making televisions, in making corrosion-resistant equipment, and several chemical applications
  • Turquoise and Tanzanites are no doubt rare gems hence their use principally in jewelry.

Gems for Zodiac Signs

Picture of Gems for zodiac signs
Picture showing Gems for zodiac signs

Zodiac signs are astrological variants of the monthly calendar. The zodiac is a region in the sky that spans about 8o north and south of where the path of the sun, the moon, and principal planets. This region contains twelve constellations although there are speculations of a 13th constellation. The zodiac is divided into twelve signs that form a celestial coordinate system. They are situated at about 30o each along the celestial longitude.

The astrological or zodiac stones are assigned based on the energy your zodiac sign receives from the constellations. Also, this list is not being regulated by anyone, unlike the monthly birthstone lists. Many times, several stones are assigned to each zodiac sign so this leaves you with a lot of options.

Birthstones by Zodiac

Table showing Gems for Zodiac signs
Zodiac sign
Corresponding Month


Ruling Planet
Birthstone (Gem)

(March 21-April 20)

Diamond, Bloodstone

(April 21-May 21)

Sapphire, Malachite, Amber

(May 22-June 21)

Agate, Chalcedony, Fire quartz

(June 22- July 22)

Emerald, Moonstone, Citrine, Silver

(July 23-August 23)

The Sun
Onyx, Zircon, Gold

(August 24- September 23)

Carnelian, Aventurine, Chrysoberyl

(September 24-October 23)

Peridot, Chrysolite, Jade, Tourmaline

(October 24- November 22)

Beryl, Rose Quartz, Rhodochrosite

(November 23-December 21)

Citrine, Topaz, Turquoise

(December 22- January 20)

Ruby, Hematite, Onyx, Obsidian

(January 21- February 19)

Garnet, Silver

(February 20 –March 20)

Amethyst, Fluorite, Chrome Diopside

Table showing Gems for zodiac signs

Birthstones by days of the week, time of birth, season, and guardian angels

Applying similar principles of assigning a birthstone to a month, days of the week are also assigned stones. When grouped like this, they are referred to as birthday stones. You might want to wear your birthstone proudly but not like the specific stone associated with your month.  These groupings by days of the week offer an alternative. The meaning associated with these stones is also similar to those for the months.

You would also find several birthstone groupings based on the hour of birth, apostles, and even guardian angels. The period of birth alone is not the only reason when you could use a birthstone. Some people wear different stones depending on the day of the week, the month, or even the season they are in. This offers a wide range of stones to choose from depending on your beliefs.

Despite the options to choose from, the list of birthstones varies from the US and the UK. Settling on one or more is totally up to you.

Birthstone by Days of the Week

Birthstone by Days of the Week
Day of the week
Yellow Sapphire
Blue Sapphire


Birthstones by Season

Birthstones by Season


History and differences in the birthstones lists

Birthstones have been around for ages now. Every culture has a history surrounding the use of gemstones in their specific culture. These uses are varied from beliefs of the gems bringing blessings to the wears to the stones having mystical powers.

Notwithstanding, the oldest records of birthstones have been traced by scholars to the Jewish culture. The Bible gives a succinct description of the breastplate to be worn by Aaron and the high priests after him. 

This breastplate was a ceremonial piece that was to be adorned with 12 stones. Each of these stones signified a tribe and bore attributes that were characteristic of the tribes they represented. These stones were to be arranged in four rows of three on the breastplate. These stones were; Sardius, Topaz, Carbuncle, Emerald, Sapphire, Diamond, Ligure, Agate, Amethyst, Beryl, Onyx, and Jasper.

Much later in the years, scholars such as Flavius Josephus (A.D.1) and St Jerome (A.D.5) drew out connections between the gemstones on the priest’s breastplate and the twelve zodiac signs. They explained that each of these stones had special powers that were heightened by the astrological sign or period they agree with. They further taught that if worn at the right time, it could afford its wearer therapeutic benefits. With this notion, the gemstones on the breastplate were assigned to the twelve zodiac signs.

As the years rolled by, the different cultures began adopting the stones to suit their culture. For instance, in Poland, specific gems became associated with individual months in the 18th century.

Traditional and Modern Birthstones

Modern birthstones came into light as an attempt to create one standard list for birthstones. This initiative was propounded by the National Association of Jewelers in 1912. This list made modifications to the earlier one that included opaque minerals gems. On the modern list, all the gemstones are transparent.

Traditional and Modern Birthstones
Peridot or Spinel
Tourmaline, and Opal
Turquoise, Lapis
Zircon, Topaz, Tanzanite

Birthstone chart showing traditional and modern stones.