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The Ultimate Guide To Birthstones - Birthstone By Month & How To PIck

Everything you need to know for the gemstone of your month. Your guide to picking your perfect birthstone, including their properties, history and other info.

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Orange spessartite garnet

When talking about garnet, most people will think of its dark red color as it’s the most common color. But actually garnet is a colorful gemstone. You can find orange, purple, pink, green, etc. And rarer ones like blue and color-changing garnet.

Anglo Saxon gold buckle with garnet inlay, 6th century. Photo from The British Museum

Garnet is quite a durable gemstone. With hardness of 6.5-7.5, it is suitable for everyday wear with the right care. Most garnet species like almandine, pyrope, spessartine, and tsavorite are on the harder side, which means they are more resistant to scratches. But demantoid garnet tends to be a bit softer. All of them can be scratched by harder minerals, like ruby, so storing and wearing them separately is recommended.

When buying garnet, stones with rich color and fewer inclusions will demand a higher price. More common colors like red and orange will be more affordable than rare colors like green and blue.

Rare green demantoid garnet with even rare horsetail inclusion which increases the gem’s value. Photo from Gem Camp




Amethyst is one of the most popular gemstones. It is the purple variation of the mineral quartz. Until the 1800’s, amethyst was as valuable as precious gems like ruby and sapphire. But when major mines of amethyst were found in Brazil, the value dropped significantly. Now it’s one of the most affordable gems you can buy.

The purple color of amethyst is associated with royalty, which is why it has been a popular gemstone for jewelry throughout history. Click here to read more about the history of amethyst.

Edwardian period amethyst heart brooch. Photo from Smithsonian National Museum of Natural History

Amethyst gets its color from the iron impurities inside the crystal structure. The color can range from light pinkish purple, to dark purple. Amethyst with a rich purple color is highly popular. It’s common to see amethyst with color zoning.

When you look for amethyst, look for a rich vibrant purple color that is not too light or dark. Purple that is too light (not intense enough color) or too dark (looks too similar to black) will have a lower value. For faceted stones used in rings, earrings and necklaces, it’s common to find amethyst that is very clean with good color. As for bracelets, look for those with as few inclusions as possible.

Amethyst is also the 6th wedding anniversary gemstone.




Aquamarine is the blue variety of the mineral beryl. Another famous gemstone in the beryl family is emerald, which is the birthstone of May.

The name aquamarine comes from Latin, which means “water of the sea”. In ancient times, sailors wore amulets made with aquamarine for protection. It has been a popular gem for jewelry throughout history.

The Schlumberger Bow. Photo from Blue Grainger Halls of gems

The blue of aquamarine comes from traces of iron inside the crystal structure. Lots of aquamarine are green-blue color. Some even have a yellow hue. Most of the aquamarines are heat treated soon after it’s mined as it can get rid of the green and yellow colors, and leave the gemstone with a purer blue color.

The most popular color is a strong sea-blue or deep blue color. One interesting variety of aquamarine is called maxixe, which has a dark blue color. However, its color fades under sunlight very quickly, and a lot of the maxixe aquamarine in the market are irradiated to achieve that color.

The Dom Pedro Aquamarine. Photo from Smithsonian National Museum of Natural History

When picking an aquamarine stone, look for one that has a rich blue color and few internal imperfections. Stones with a green and/or yellow hue will be more affordable. It’s easier to find clean stones for rings, earrings and necklaces than beaded bracelets. For beads and bracelets, look for those that are translucent or transparent with minimum fractures.



Another birthstone for March is bloodstone. It is a green variety of the mineral jasper with red spots on the stone that resembles blood spots. It is also known as heliotrope.

The red part of bloodstone is caused by the mineral hematite, while the mineral goethite produces the yellow and brown parts.

Bloodstone is an inexpensive choice compared with aquamarine. A dark green bloodstone with an abundance of red flecks is considered high quality. But some people also prefer the more colorful bloodstone with different shades of green, red and yellow.

Bloodstone box with gold leaf ornaments. Photo from Hillwood museum



Possibly the most famous and popular gemstone, diamond has long been a favorite for weddings and engagements.

With a hardness of 10, diamond is the hardest gemstone and mineral in the world. But that doesn’t mean that it’s unbreakable. Story goes in the early days of prospecting for diamonds, many struck a sledgehammer to test whether the diamond is real. Many fine diamonds were possibly destroyed by this method.

The famous Hope diamond. Photo from Smithsonian National Museum of Natural History

The quality and price of diamond is determined by the 4C’s: Clarity, Color, Cut, and Carat.


Generally, the higher the clarity, the more valuable the diamond is. Also, the location of the flaw also plays a part. If the flaw is near the center, it will lower the value more than if the flaw in on the side.


The more colorless the diamond is, the more valuable it is. However, when the color intensity reaches a certain point, the diamond will be considered fancy color diamond, which is very rare and highly desirable.

DeYoung Red Diamond. Photo from Smithsonian National Museum of Natural History


A good diamond cut will allow light to enter the diamond, reflects inside the gem, and comes back out to the top with slight flashes of color, which is known as fire. In general, the brighter the diamond because of the cut, the better its quality.


Carat refers to the weight of diamond. 1 carat is 0.2 gram, and diamond is weighted to 1/1000 of a carat. A heavier diamond will be more expensive in general, but the price also depends on the other factors.



Emerald is the green variety of the mineral beryl. Another famous beryl gemstone is aquamarine, which is the birthstone for March. Emerald is a rare and precious gemstone alongside diamond, ruby and sapphire.

Elizabeth Taylor's emerald and diamond BVLGARI pendant, sold for over US$6 millions. Photo from Cristie's

Emerald gets its color from traces of chromium and possibly vanadium. Only dark rich green colored beryl is considered emerald. Lighter color ones are usually considered green beryl.

Nearly all emeralds have inclusions like cracks and fractures. They are so common that dealers have a name for them, called “jardin,” or garden. A sizable flawless emerald is almost impossible to find. Therefore, color is a big part of determining the price and quality of emerald. A high quality emerald should have a rich, but not too dark, green color. It is extremely rare and valuable, even more so than diamond.

When choosing for beads or bracelets, the emerald will usually be opaque (not see-through), and the color will be the most important factor.

Another valuable variety is tripache emerald. Photo from New Era Gems



The Express Ring with moonstone and color-changing garnets. Photo from GIA

Moonstone is one of the most popular semi-precious gemstones because of its blue/white glow, called adularescence. When you view a moonstone from different angles, the glowing sheen that floats across the surface. The effect is caused by light entering and scattering among microscopic layers of the structure of the crystal.

When choosing moonstone, look for those with a strong glow/sheen, preferably in the center. The body color of the moonstone should be colorless or white, though there are other variety of moonstones like peach moonstone and black moonstone that have different body colors. For clarity, a transparent or translucent moonstone with minimal visible flaws is the best.

Raw moonstone crystals


Color-changing Alexandrite. Photo from GIA

Alexandrite is a rare color-changing variety of the mineral chrysoberyl. It is often described as an “emerald by day, ruby by night”. A high quality alexandrite changes colors from bluish green in natural light and purplish red in incandescent light. An even rarer type of alexandrite is ones that display a cat’s eye effect in addition to the color change.

High quality alexandrite with strong color change and high clarity usually only found in less than 1 carat. The price will increase dramatically with the size. One of the most notable alexandrite is this whopping 17.08 carat Whitney Alexandrite.

Whitney Alexandrite. Photo from Smithsonian National Museum of Natural History


Pearl is an organic gem, and the only gem that is made by a living creature. Pearl is created when an oyster or mollusk covers a foreign object with layers and layers of nacre, which is mainly made up of calcium carbonate. The resulting pearl has an iridescent, mother-of-pearl-like shine.

A lot of the pearls in the market now are cultured pearls, which involves artificially putting a small object in the pearl-producing creature in order to trigger their defense mechanism. So that it will build a pearl around the object that’s put in.

Pearls can be white, gold, black or even multicolored. Natural pearls are more expensive than cultured ones. Pearls that are perfectly round and without blemishes on the surface are highly valued.

Dunn Pearl Necklace. Photo from Smithsonian National Museum of Natural History



Ruby is such a romantic gemstone. This precious gemstone is a red variety of the mineral corundum. The red color of ruby comes from traces of chromium.

Color is the most important factor in determining the value of ruby. A high quality ruby needs to have a vibrant red color. A deep red ruby with a slight purple tint is sometimes known as pigeon red ruby. The red color can’t be too dark as it lowers the brightness of ruby, or too light as a pink colored gem is usually considered pink sapphire instead of ruby.

A pigeon red ruby. Photo from Leibish Co.

Ruby is usually included. A fine quality ruby with no flaws is almost non-existent. That being said, the clearer the ruby, the higher the price will be.

Some rubies are called star rubies as they show 3 rays of light reflections. This effect is called asterism and it increases the value of ruby.

Ruby with good color and good clarity is usually cut and faceted for rings, earrings and pendants. For bracelets and beads, color is a more important factor as almost all the ruby used for them are opaque and not see-through.

The Delong star ruby. Photo from Reddit



Raw peridot crystal. Photo from iRocks

Peridot is the green variety of the mineral olivine. Most peridots are formed deep inside the earth and are brought to the surface only by volcanic activities.

The colors of peridot can range from yellow-green, brown-green to olive-green. The best color will be a deep olive- or grass-green color without yellow hue. Most peridot found in the market has a yellow-green color.

Faceted peridot. Photo from King Stone Gems

Smaller faceted peridot in the market is usually without visible imperfections. Bigger peridot with no flaws will be harder to find and more expensive.

However, the peridot used for beads and bracelets has more flaws like internal fractures. Those may require extra care as fractures will increase the chance of the gemstone breaking.

Sometimes peridot will have disk-shaped inclusion known as lily pads.

Lily pads inclusion of peridot. Photo from GIA


Some famous ‘rubies’ in the history turns out to be actually red spinels, and some ‘sapphires’ are actually blue spinels. This is because the colors of spinel can rival a top quality ruby or sapphire. Also, spinel is formed under very similar geological condition to those gemstones.

birthstone-august-spinel-black-prince ruby
The Black Prince's 'Ruby' on the Imperial State Crown. Photo from Wikipedia

Other than those two colors, spinel also comes in many other colors like pink, purple, yellow, etc. The most expensive colors are ruby red, sapphire blue and other bright and vivid colors. Colors like light pink and lavender will be more affordable.

Because of the similar look as ruby, some people consider spinel to be an alternative. For the same size, a top quality spinel may only be 1/10 of the price of a top quality ruby.

Blue spinel from Sri Lanka. Photo from Smithsonian National Museum of Natural History


Sardonyx is a orange to brown colored gemstone with white colored bands. The bands are usually straight, compared to the curved bands of agate.

It’s closely related to two other gemstones, onyx and carnelian. Onyx is a black and white version of sardonyx, but it doesn’t have traces of iron oxide that gives it the orange color. Carnelian usually has a more reddish color.

Compared to other birthstones, sardonyx is a much more affordable gemstone. You should look for those with good contrast between orange and white colors, and those with no flaws like black spots.

However, some sardonyx in the market are dyed to achieve the color. Look for stains or concentration of color in some parts of the sardonyx, especially in the cracks and fractures. Those are the signs that the stone is dyed.



You may think of blue when you think about sapphire. But sapphire actually comes in many different colors except red, as red colored corundum is ruby. Usually sapphire that is not blue is called fancy color sapphire.

Sapphire comes in many colors. Photo from GIA

Sapphire is a rare gemstone. For blue sapphire, the best color is a vibrant deep velvety blue, but the color can’t be too deep that it lowers the brightness of the stone. For other colors, the more vivid and saturated, without lowering brightness, the better.

The clarity of sapphire is also important. Although flawless stones are still very rare, sapphire is generally cleaner than ruby and emerald. When looking for a sapphire, a sapphire with fewer flaws will demand a higher price. An opaque sapphire will be much more affordable than a translucent or transparent one.

Sapphire with chatoyance, or cat’s eye effect, will demand a higher price. Star sapphire will be even more expensive.

If you are buying a sapphire bracelet, color will be the most important factor as almost all sapphire used for bracelet will not be see-through.

The Hall Sapphire Necklace. Photo from Smithsonian National Museum of Natural History




Opal is one of the most beautiful and most famous gemstones in the world. The name opal comes from the Roman word opalus, which means “precious stone”. Precious opals flash rainbow colors when you turn the stone. This effect is called play-of-color. The best quality stones are those with a bright color play displaying all the colors of the rainbow.

The silica spheres inside precious opal is the responsible of producing the rainbow colors. When light enters, the spheres bends and refracts the light, causing the beautiful rainbow colors. According to GIA, the spheres that are about 0.1 micron (one ten-millionth of a meter) produce violet colors. And spheres that are about 0.2 microns in size will give red colors. Sizes in between produce the remaining rainbow colors.

Boulder opal

There are a few types of opals. Possibly the most well-known are white opal and black opal. They both have play-of-color on white and black body color crystals respectively. Boulder opal display play-of-color with a host rock, called matrix. Fire opal or Mexican opal has an orange translucent body color and doesn’t have color play. Crystal opal has play-of-color on a transparent background. And finally common opal which is opaque and doesn’t display color play.

When picking opal, generally look for those with strong play-of-color with a wide range of colors. The brighter and more colorful, the more expensive the opal will be. Black opal is generally the most expensive type of opal.

Opal has a high amount of water in its crystal structure, about 6-10%. And losing that moisture would make the opal crack. That’s why it’s important to avoid extreme heat and sunlight, or storing the opal in a dry environment.


Bi-color tourmaline (watermelon tourmaline)

Like garnet, tourmaline is actually a group of at least 14 species, each with their own chemical makeup. But they share a similar crystal structure. In the jewelry world, tourmaline will be known for their different colors instead of the complex chemical composition. Most gem quality tourmaline is of the elbaite tourmaline species.

Some of the tourmaline varieties:

  • Rubellite (red)
  • Indicolite (blue)
  • Verdelite (green)
  • Canary (yellow)
  • Schorl (black)
  • Cuprian (vivid ‘neon’ colors including the paraiba tourmaline)

Green Verdite Tourmaline

And some tourmaline has more than one color in a single crystal. One famous variety is watermelon tourmaline, which usually has green and red colors.

Interestingly, tourmaline can be electrically charged when under pressure (known as piezoelectric) and changing temperature (known as pyroelectric). Other than industrial usages, this also means your tourmaline jewelry will tend to collect more dust over time because of the (small) electric charge over time.

Electric blue tourmaline. Photo from GIA

When choosing tourmaline, there are a few factors that affects the price. The more intense the color and clearer the crystal is, the more expensive the gem will be. Some colors are more expensive than the others, like blue and paraiba colors. Usually brown and black are the cheapest. If the tourmaline shows a cat’s eye effect, the price will be higher.



Half-polished blue topaz crystals

A lot of people know topaz as the blue colored gem – Blue topaz. But this gemstone has so many more colors than that.

Other than blue, topaz can be yellow, red, pink, purple, etc. A specific color of topaz is orange-red of the imperial topaz, which is the most expensive and rare type of topaz.

Golden imperial topaz. Photo from Smithsonian National Museum of Natural History

Blue topaz in the market is irradiated and heated to achieve the color. The blue color is stable and is attractive to a lot of mass market customers. And out of the many colors of topaz, blue is the most affordable.

When buying topaz, color will be a big factor in the price. Colors like blue, yellow and colorless are cheaper and easier to find gems that are flawless. The higher the clarity and the more intense the color, the higher the price tag of the topaz will be.



This beautiful yellow gemstone is a variety of the mineral quartz. Its name comes from the word “citrus” because of the color. The color can range from light yellow to golden yellow. Traces of the element iron gives citrine the beautiful yellow color.

Natural and untreated citrine can be quite rare as a lot of the citrine in the market are treated. A common treatment is to heat some types of amethyst to turn them yellow. The intensity of color can be determined by the temperature. A lower temperature will produce a light yellow, while a higher one will give a golden orange color. Smoky quartz can also turn yellow after heating. Also, natural citrine itself will have a more intense yellow color after mild heating.

Victorian 15K citrine and amethyst brooch. Photo from Rubylane

When you look for citrine, the more intense the color and higher the clarity, the more expensive the crystal will be. However, especially when shopping for citrine bracelet, be aware of extremely clean citrine with no visible flaws with a low price tag. They are most likely hydrothermal quartz, made by synthetic process in a laboratory or a factory. To simply put, a ‘seed’ material in placed inside a chemical solution where crystals are grown. The result is quartz that have no inclusions or color-zoning.

A huge 19747ct citrine from Smithsonian National Museum of Natural History (Photo credit)




Turquoise has a distinct blue green color that is loved by many. Other than its attractive color, turquoise has a long history. It’s long been used in jewelry and carving in ancient Egypt and China.

A famous type of turquoise is one with an even vivid sky blue color and no veins or webbing visible, and that’s called sleeping beauty turquoise. It is highly prized and rare. However, sometimes the veins and webbing pattern (known as ‘matrix’ of turquoise) is intricate and uniform, it raises the price of turquoise as well. This type of turquoise is called spiderweb turquoise.

Turquoise Zuni Bracelet. Photo from Smithsonian National Museum of Natural History

When buying turquoise, you should know that most turquoise is stabilized. One of the reasons is that because turquoise is porous, unstabilized turquoise is prone to decolorization and fractures.

Because of the high price of sleeping beauty turquoise, there are quite a lot of dyed, imitation and fake stones in the market. One of the main one is blue dyed howlite. It has a uniform blue color with some brown webbing pattern. Another type is a uniformly colored reconstituted turquoise. It uses crushed turquoise mixed with other materials like plastic and resin, and mold it into desired shapes. If the price of turquoise seems too low, it’s probably fake or treated. Buy from reputable jeweler to ensure that the turquoise you buy is genuine.



One of the newest favorites of the gem market, tanzanite is a dreamy blue violet colored gemstone. It is discovered relatively recently in 1967, and it’s only found in the hills of Merelani in northern Tanzania. With the increasing demand, the price of tanzanite has climbed ever since its discovery.

The best color of tanzanite is a violet blue color. As tanzanite has the property of pleochroism, it shows different colors when viewed from different angles. For example, a tanzanite can show a sapphire blue or a violet blue depending on the viewing angle. Almost all tanzanite in the market in heated to remove the brown and yellow hues from the gemstone.

A faceted tanzanite. Photo from Smithsonian National Museum of Natural History

Blue Zircon

A faceted blue zircon. Photo from Smithsonian National Museum of Natural History

Zircon is not well known to the mainstream market as it’s often confused with cubic zirconia, a man-made synthetic diamond. Also, natural colorless zircon is sometimes used as a diamond look-alike because zircon can also produce multicolor fire like diamond.

Zircon actually is a colorful gemstone with colors like blue, red, green and more. Blue is by far the most demanded color of zircon. Zircon is almost always heated to achieve this blue color.

Other than color, another factor in determining the price of zircon is its clarity. The clearer the gemstone, the higher the price will be. In some stones, when the inclusions are parallel to each other, zircon can show a rare cat’s eye effect, and that can raise the price as well.

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