24 Gray Gemstones (How Many Do You Know?)
14 Minute Read
Nothing communicates quiet luxury like jewelry set with gray gemstones. Regardless of size, gray gemstone jewelry is incredibly versatile and can make any outfit look sophisticated, confident, and elegant. Plus, gray is a color that can be paired with any other hue, so you can wear your jewelry with virtually everything in your closet! Fortunately, there are quite a few gems that show a gray color for you to choose from.
Gray, like black and white, is technically not a color. It only exists on the spectrum of tone (lightness and darkness) alone. Being achromatic, gray gems are stones whose tone is neither fully dark (which would be black) nor fully light (which would be white). That is not to say that all gray gems are without color. Some can exhibit minor contributions of colors like violet, blue, brown, and even green.
When diamonds display a light gray color, they are classified within what gemologists call the normal color range and fall within the category of "colorless diamonds". Should the gray color of a diamond be so pronounced that it is too dark to be classified as colorless, it is then referred to as a "fancy-color diamond". This is true of yellow and brown colors as well.
Scientists have described several reasons explaining what triggers a gray color in diamonds. For example, when the chemistry of gray diamonds is analyzed, an unusually high percentage of hydrogen atoms is often detected, leading to the theory that hydrogen is one of the possible coloring agents for gray stones.
A second trigger for a gray color is the presence of dark graphite inclusions that are small and numerous enough to darken the appearance of colorless diamonds. Whatever the reason for their color expression, gray diamonds generally have much lower price-per-carat costs when compared to other fancy-colored diamonds.
Sapphire with a dominant gray color exists, but it is hard to find. This is because most natural gray sapphire gems are treated to remove the color and induce a different, more valuable dominant hue.
Gray sapphires may show some blue or brown secondary hues, but their color can appear muddy. More often, you will find sapphires with primary colors like blue or green that are modified by minor amounts of gray. If you do find an untreated gray sapphire, it's price-per-carat cost will likely be low.
Unlike the generally shunned gray sapphire, gray spinel has become a highly fashionable gem in the last decade, causing the price-per-carat value to skyrocket. Gray spinel may show a secondary hue of blue or violet, and many buyers prize gray spinel with a delicate lavender color thanks to a small contribution of purple. Spinel is a hardy stone that can take on a high polish and maintain that sheen for many years even with regular wear. As one of the birthstones for the month of August, spinel jewelry is a great gift for people who want something that they can wear every day.
Classifying opals with a gray body color can get a little tricky. Technically speaking, there is not an official "gray" opal category, rather, very dark gray gems fall within the umbrella of black opals while light gray gems are clumped with white opals.
The only type of garnet which can be a dominant gray is the hydrogrossular variety. Hydrogrossular garnets are anomalies within the wider garnet species in that they are the only type of garnet that cannot have transparent clarity, rather, you will find translucent to opaque gems exclusively. In addition to purely gray gems, you may also see stones mixed with low saturations of pink, purple, or green. It is not unusual for hydrogrossular garnets to have small flecks of black inclusions scattered throughout their crystal.
Chalcedony is a type of quartz, an abundant material in Earth's crust. As chalcedony is an aggregate comprised of microcrystalline-sized pieces of individual quartz crystals, it both looks and feels very smooth when polished. Chalcedony stones can be a solid color, but they are famous for often having straight-colored layers or curved bands which create a dynamic swirling effect.
Always displaying a clarity of semi-translucent to opaque, chalcedony gems with a mostly pure chemical composition are a light gray color. Unfortunately, many consider gray chalcedony to be dull when compared to other possible hues, leading to gems often being treated to achieve other colors including a popular black. High-quality gray chalcedony with a translucent clarity looks very similar to lovely blue moonstone.
Moonstone is part of the most widespread group of minerals on Earth - the feldspar family. Specifically, moonstone is made from two types of feldspar which are neatly layered on top of each other: orthoclase and albite. The body color of moonstone can be gray in addition to colorless, brown, yellow, green, and a dark gray that is almost black.
It also has a unique phenomenon named for it: "adularescence." This phenomenon looks like light contained within the gem that freely billows around. The name adularescence is derived from the word "adularia" which was an ancient name for moonstone, and it happens when light gets trapped and scattered between the layers of different feldspars. While the best moonstone is colorless with blue adularescence, gray gems can also show the phenomenon quite well. To highlight adularescence, this June birthstone is often made into cabochons or carved with images like the face of the man in the moon.
Another type of feldspar, labradorite is a close relative of moonstone. Named for Labrador, Canada, the location where the first labradorite was uncovered, some labradorite shows a dynamic phenomenon called "labradorescence." Labradorescence is a shimmering effect shining within the stone which reflects brightly when the light hits the gem from the proper angle.
Depending on where the gem was mined, a stone's labradorescence may show combinations of blue, green, red, orange, and yellow. This effect looks different from adularescence because the light appears to shine from a solid surface inside the stone rather than suspended in a transparent crystal.
A quick note: when searching for moonstone jewelry, you may come across gems called "rainbow moonstones" which exhibit multicolored adularescence. These gems are actually a special type of especially transparent labradorite that is most often recovered from Madagascar.
When someone mentions "zircon", many think of the synthetic cubic zirconia which has been used as a diamond simulant for years. However, zircon is an independent and natural gemstone species that can exhibit a range of beautiful colors rivaling other colored gems like sapphire and spinel. Buyers may not realize that this birthstone for the month of December can be a delightful gray color, sometimes with low levels of blue or brown hues. Zircon boasts high dispersion which creates lots of distinctive rainbow-colored flashes regardless of body color. This is a very rare trait amongst the various colored gemstones. Unfortunately, zircon is sensitive to heat which makes cutting it a risky task. Also, it is rather soft with a Mohs score of 6-7 ½, so its' surface can accumulate scratches over time if you aren't careful.
Gray jade is not the most popular color for this gem, but that means that you can find lots of relatively affordable jewelry. Both jadeite and nephrite, the two subtypes of jade, can be a pure or dominant gray color. While the best jade has a semitransparent clarity, it more often is translucent to opaque. As such, you are going to see jade fashioned into beads, carvings, or hololiths (rings or bracelets chiseled from a single block of jade). A centuries-long favorite of Far East cultures, there is quite a bit of lore surrounding jade and many continue to believe that the gem offers protection to its wearer.
One of the birthstones for November, topaz can take on many different colors, but, sometimes, those colors are poorly saturated, leading to a strong gray color component. Due to its naturally columnar crystal structure, topaz is often cut in long oval or pear shapes. Topaz is famous for the tremendous size that some crystals can grow. In fact, weighing in at almost 23,000 carats, the Brazilian "American Golden" topaz owned by the Smithsonian Institution is one of the largest faceted gemstones in the world.
This second birthstone gem for the month of October is known for its vibrant colors, but very rarely gems are found with a dominant gray color. Sometimes the body color of gray gems is modified by another hue such as blue, brown, pink, or green. Like all tourmaline gems, you will often find gems faceted into elongated shapes like emerald cuts mimicking the form of the natural crystal. Tourmaline attracts buyers both as a faceted gem and in its raw crystalline form.
The beryl family of gemstones includes some of the most popular species out there including emerald, morganite, heliodor, and aquamarine. Similar to topaz, some blue beryl gemstones have poorly saturated hues which adds a significant amount of gray to their color expression. Such gems are simply called "precious beryl" and their transparent clarity is often quite clean.
Unlike some of the other gems on this list which exhibit gray only rarely, the common form of spodumene is, in fact, a gray color with cloudy clarity. The name "spodumene" comes from the Greek word for ashen, "spodeios", referencing this distinctive hazy grayish color. A relative of jade, the spodumene family has three subcategories, the most famous of which is the transparent pink kunzite. Due to the cloudy, unexciting appearance of gray stones, spodumene is not often used as a gemstone.
Thanks to the nineteenth-century discovery of how to culture this June birthstone, we now have access to the gem in a huge variety of sizes and colors, gray included. There are four primary types of cultured pearls for buyers to choose from: Akoya, Freshwater, South Sea, and Tahitian. Of these species, Tahitian pearls can be true gray thanks to their parent mollusk species having black-lipped shells. The body color of the best gems is modified by an overtone color which can be purple, pink, blue, green, or yellowish green. With a Mohs score of 2 ½ -3, pearls are very soft and at risk of drying out. Always be careful to store gems in a soft cloth and wear them periodically so that they can absorb the natural oil from your clean skin.
Hawk's Eye Quartz
Hawk's Eye quartz is the gray cousin of its better-known relative, the brown Tiger's Eye. Displaying a characteristic stringy cat's eye effect, Hawk's Eye quartz is usually sold as beads or tumbled stones. Found in many places, some believe that the clear chatoyancy of Hawk's Eye quartz helps sharpen the intuition of its wearer.
Never fully transparent, serpentine is a soft gemstone that may have inclusions such as black spots, white veins, or moss-like patterns. There are several subtypes of serpentine including the bowenite variety which is the strongest of the family with a hardness score up to 6. Unfortunately, even bowenite can be easily scratched even when rubbed against other materials. As such, it is best to wear serpentine gems as necklaces, earrings, or brooches. The most transparent stones may be faceted, but you are more likely to find carved pieces.
The relatively unknown sillimanite is a lovely translucent gray gem that can show a bright cat's eye effect. Gray gems may have secondary colors like green, blue, violet, or brown. This rare gem named after mineralogist Benjamin Silliman was first uncovered only recently in the 1990s in India. Now found in several locations worldwide, ethereal sillimanite can be a wonderful addition to your collection.
Hematite is an iron-rich gem that can have a dark gray to black body color. An unusually heavy gem, hematite is an opaque stone often used as the base for intaglio carvings and subsequently set in signet rings or hung as pendants. Over time, the exposure to oxygen will cause the iron to oxidize resulting in a reddish coating over the surface of the stone.
The ocean is a beautiful, multi-colored environment thanks to plants and animals that showcase a rainbow of hues. Shells of marine animals can be found in many colors, gray included. Some shells show a shimmering mother-of-pearl effect called an "orient". Always translucent or opaque, shells are one of the most ancient substances used by mankind as adornment with some items dating well over one hundred thousand years old. Today, look for shell beads, buttons, or cameo carvings.
Ammonites were a type of cephalopod family comprised of multiple individual species that went extinct 66 million years ago at the same time as the dinosaurs. Relatives of the modern-day octopus and squid, they were an incredibly successful group of species boasting beautiful flat spiral shells. Fossils are uncovered ranging in diameter from just a few millimeters to almost two meters. The best ammonite fossils show exceptionally strong iridescent colors making them perfect for use in jewelry or decorative items. Jewelers may choose to polish intact shells or slice the fossil in half lengthwise to create a matched pair.
Obsidian is a type of volcanic glass that forms when hot magma erupts and cools so rapidly that minerals don't have enough time to crystalize. Obsidian's claim to fame is its incredibly sharp edge which can be thinner than most surgical blades. Most are familiar with the black variety of obsidian, but it can take on other bodycolors including dark gray. Obsidian displays multiple colors like purple, black, and green and is called "rainbow obsidian". Dark obsidian with numerous white spots is called "snowflake obsidian".
Idocrase is an attractive gem whose reputation unfortunately rarely expands beyond the collector's market. In addition to gray, idocrase can exhibit red, yellow, green, and brown colors. Perhaps part of the reason for the anonymity of this gem is the fact that its appearance can often overlap with other, more well-known gems like jade and hydrogrossular garnet. In some cases, this similarity extends beyond the appearance as it is not uncommon for the chemical makeup of idocrase gems to be mixed with hydrogrossular garnet, creating a blended stone. Interestingly, a large deposit of idocrase/hydrogrossular melded gems was unearthed in California, and those gems were later labeled "californite". In fact, the name "idocrase" is a blend of two Greek words, idos and krasis. Together, those words translate as "mixed appearance".
Horn that has historically been used in jewelry can come from many different animals, and, depending on where on Earth they live, conservation laws may or may not be in place to protect them. One example of legal horn harvesting is the collection of Vietnamese water buffalo horns. These animals are not harvested for their horn specifically, rather they are gathered as a byproduct of agricultural practices. Finding affordable buffalo horn jewelry is quite easy and it makes for a unique and playful adornment material. The color of horn can range from light yellow to almost black and it's clarity ranges from semi-transparent to opaque.
Emily Frontiere is a GIA Graduate Gemologist. She is particularly experienced working with estate/antique jewelry.
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