Read on to learn how to assess quality in blue gemstones, from popular and well-known species to rarely seen specimens. In addition, you’ll learn which stones will hold up best in rings and other jewelry and which should remain safely in a viewing collection.
Assessing Color and Quality in Blue Gemstones
Gemologists assess color by considering hue, tone, and saturation. Gemstones often have a secondary hue in addition to a primary hue. For blue gemstones, common secondary hues are green and violet. In general, a more pure blue hue is desirable, and when a stone strays further from blue, it’s less valuable. Still, greenish blue and violetish blue gems are quite attractive! Blue sapphires with slight violet hues are still top color. Other gems, such as paraíba tourmaline, more commonly exhibit green secondary hues.
Blue hues reach top saturation, or intensity, at medium-dark tones, about 85%. This is called the gamut limit. Vivid saturation is an eye-popping color. Darker tones will appear inky or steely, while lighter tones may appear washed out or gray. Nevertheless, beautiful blue gemstones occur in a wide range of tones, from light, sky blues to deep, dark colors.
Clarity grades have much less importance in blue gemstones than in colorless stones. Since the color can mask inclusions, it makes them less noticeable. However, avoid large inclusions or fractures, as these can still make the stone more breakable. For lighter toned blue gemstones, a somewhat better clarity grade will improve the gem’s appearance. In such cases, avoid dark inclusions, as these will be readily apparent in a light gem.
If you’re considering a blue gemstone for an engagement ring or fine jewelry, consider designing a unique piece with CustomMade. Their experts can help you find a top-quality stone, and you’ll avoid the poor quality that most major retailers offer (like this overly dark sapphire from James Allen).
Blue Gemstones Ideal for Everyday Wear
If you’re looking for a blue gem for a ring, the following types are your best bets. Each of these stones rates at least a 6.5 on the Mohs hardness scale, making them resistant to scratches. Better yet, they’re less likely to break when accidentally dropped or knocked against a table. These tough blue gemstones will hold up to everyday wear, making them ideal for engagement rings. With regular cleaning, they’ll also keep looking as good as the day you bought them.
By far the most popular blue gem for faceting, a blue sapphire can have very high saturation. Royal engagements have also made it one of the most popular choices for engagement rings! This September birthstone can occur in any color except red (which is ruby), but its classic and most well-known hues are blue to violet. These hues arise from trace amounts of titanium and iron in the gem’s crystal structure. Sapphires often undergo a heat treatment, which improves their clarity and color.
If a natural sapphire is out of your price range, consider a lab-created stone. These have the same durability and beauty as natural stones, but at a fraction of the price.
Tourmaline (Indicolite and Paraíba)
A modern option for the October birthstone, tourmalines have recently increased in popularity and price. Tourmalines occur in every color, but blue specimens, called indicolites, are rare and highly prized. Due to their rarity, finished indicolite gems will contain inclusions and fractures more frequently than other color varieties of tourmaline.
Most blue tourmaline contains tiny amounts of iron, which give it color. Some indicolites undergo heat treatment. This undetectable process creates a lighter but stable color.
Some indicolite contains copper. These stones, first found in Brazil in the 1980s, were named “paraíba tourmaline” after the original source area. However, miners have since discovered copper-bearing tourmalines in other parts of the world. Paraíba tourmalines have bright, neon-like blue-green colors that wowed the gem industry when they hit the market. These gems routinely undergo heat treatment to improve color, and some even have clarity enhancement similar to emeralds.
Known for watery blues and blue-greens, aquamarine never reaches the dark tones and high saturation of sapphires and tourmalines. Nevertheless, darker tones hold more value, even if the stone is somewhat gray. In the past, the beloved modern March birthstone was used as a talisman to keep sailors safe at sea.
These stones routinely undergo heat treatment to lessen green hues, resulting in a more pure blue. However, some aquamarines don’t alter with this treatment and remain an unusual yet attractive sea-foam blue-green.
Long overlooked by the public but a favorite among gemologists, spinel is slowly gaining the recognition it deserves. Recently declared a modern option for the August birthstone, spinel occurs in a wide variety of colors, including blue. Though many are too dark to properly see the color, medium tones of intense saturation are beautiful to behold. Cobalt-colored spinels are particularly prized for their bright, intense blue colors. Synthetic spinels, common and inexpensive, are frequently used as simulants or imitations for many gems.
Widespread in both inexpensive jewelry and designer pieces, turquoise is the most popular of blue gemstones. It ranges in hardness from 3 to 7.5, depending on the mineralogy of its host rock. Thus, some turquoise is highly resistant to scratching, but most will scratch easily. A December birthstone with ancient symbolism, turquoise is beloved by many. However, low-grade turquoise often undergoes stabilization or receives dye to intensify its color. Some imitations are even sold as reconstituted turquoise. Buyer beware.
On the more expensive side, fancy colored blue diamonds are quite rare but have a beautiful brilliance and dispersion, or fire. Though naturally colored gems rarely reach high saturation, gems treated with irradiation and heat, or through the HPHT process, can have strong color with little gray. Lab-created diamonds may also be blue.
This diamond has great color but contains many inclusions. Fancy Intense Blue Diamond HPHT 3 carat Princess cut #31854 from R. Rothem Diamonds on Vimeo. Licensed under CC By 3.0.
Lovely translucence and low cost have prompted a slight resurgence in the popularity of chalcedony. Blue hued chalcedony, called chrysocolla, can have gray or lavender secondary hues. A new variety, colored by nickel and chromium, has bright blue-green hues. You’ll find it marketed as aquaprase™. Lapidaries often create cabochons or carvings from these stones to best show off the color and translucence.
One of the world’s rarest minerals, jeremejevite occurs in only a few places. Gem-quality specimens from Namibia exhibit light, aquamarine-blue hues. Transparent crystals from other locales are uncommon. In spite of its rarity, some lapidaries have faceted this gem. With a hardness of 6.5 to 7.5 and no reported cleavage, this ultra-rare gem is durable enough for regular jewelry wear!
If you’d prefer a more unique cabochon, dumortierite makes an excellent jewelry option. Blue to violet-blue, this often massive material is uncommon but can be quite beautiful. Its rare occurrence in crystalline form means that few pieces can be faceted. In certain specimens, dumortierite inclusions in quartz create mesmerizing structures reminiscent of a coral reef.
Named for blue hues that can resemble sapphire, sapphirine can have light to dark, blue to blue-green hues. Fine, facetable crystals are rare and collectible. Some transparent specimens occur in Sri Lanka, but other locales usually don’t produce high-quality blue gemstones. However, with a hardness of 7.5 and poor cleavage, this gem is durable and will hold up well in jewelry.
With delightful chatoyancy, hawk’s eye stones are a pleasure to observe. These stones are the blue version of tiger’s eye. While iron has colored tiger’s eye golden brown, this hasn’t occurred in hawk’s eye. Thus, the titanium blue of the stone shows through.
Once a favorite of the ancient Mayans, blue jadeite is very rare. This stone, which occurs only in Guatemala, is often somewhat gray. Nonetheless, jadeite is one of the toughest gems and is even known for its musical qualities. If you hit jade with a hammer, it will ring like a bell!
Blue Gemstones for Occasional Wear
Unfortunately, not all blue gemstones are tough. Some are soft or prone to chipping. The following gems are best suited for earrings, pendants, and brooches. If you’re creating a ring with one of these gems, use a protective setting to minimize wear.
Found only in a small area of Tanzania, this stone’s popularity has skyrocketed in recent years. Intense blue and violet hues, the result of heat treatment, mimic fine sapphire at a fraction of the price. However, tanzanite can easily chip or break if knocked against a surface. Still, this rare stone makes a beautiful alternative to sapphire.
This June birthstone option has an unusual sheen called adularescence. In many specimens, this appears as a cloud of blue floating within a milky white stone. Top-quality moonstone has a bright, medium blue adularescence on a colorless body. Lapidaries usually carve such stones or cab them with high domes. This variety of feldspar is somewhat soft and prone to chipping, so be sure to store it away from other stones.
Though it never reaches the saturation of fine sapphire, iolite can serve as an excellent and inexpensive alternative. With low prices and a lack of known gem treatments, some gemologists consider iolite an underappreciated stone. This gem’s intense pleochroism, appearing dark blue from one angle but light yellow from another, is wonderful to behold. Furthermore, this mineral may have some historical importance. Some historians suspect this was the “Viking Sunstone,” used for navigation at sea. Nevertheless, this stone can break in two if improperly handled.
The term “apatite” refers to an entire group of minerals. However, you’ll often see it used alone to refer to apatite gems. Though these gems occur in almost any color, the bright, neon blue-green material from Brazil is especially spectacular. Still, apatites are heat sensitive and brittle, so use caution when setting them in jewelry. Never clean them with mechanical or heated cleaning systems.
In the Dominican Republic, the fibrous mineral pectolite grows in a dense blue form known as the gemstone larimar. While quite tough, this gem rates at best a 6 on the Mohs hardness scale, making it somewhat prone to scratching. This rare gem makes for a great souvenir and a unique gift for gem collectors.
If a blue diamond is out of your price range, consider benitoite. This gem has more dispersion, or fire, than diamond, and, in spite of its rarity, is less expensive, too! While still not a cheap gem, this unique California stone will turn heads for its deep blue color and bright fire. However, with a hardness of 6.0-6.5, it may develop scratches over time. Due to its brittle nature, this blue stone should be well protected in a jewelry setting.
Another underappreciated gem, zircon has dazzling brilliance and fire. Often confused with the synthetic material cubic zirconia, buyers may overlook this natural stone in favor of another gem. Still, bright blue hues in this modern December birthstone are attractive and often have a strong green component. While this stone may chip, its beautiful sparkle makes it an attractive and affordable choice for jewelry.
With symbolism thousands of years old and bold royal blue hues, lapis lazuli is one of the most popular blue gemstones. While somewhat prone to scratching, lapis is tough and, due to its abundance and low cost, can be easily replaced if damaged. While most of the world prefers a solid, even blue color, some American connoisseurs prefer a smattering of pyrite inclusions, which appear in the dark blue stone like stars in the night sky.
This November birthstone is best known for reddish and yellow hues, but the advent of irradiation and heat treatment has given rise to inexpensive and attractive blue topaz stones. Treatment produces stable colors in gems that remain perfectly safe for wear. While topaz is somewhat prone to chipping, proper cutting angles should reduce this risk.
In a class of its own, this October birthstone is one of the most eye-catching gems. Opal also has a rich folklore. In blue hues, a precious opal’s play of colors can resemble sunlight on the ocean’s surface. Even common opal in blue hues is quite attractive. Nevertheless, these stones are soft and may be scratched when exposed in jewelry. Furthermore, opals from some mines may craze, or crack, when they dry out. Covering an opal with a hard top stone as a triplet will protect it from scratches, and proper care will go a long way in keeping your gem beautiful.
Though faceted lazulites are very rare and too brittle for jewelry, cabochons of massive material are more stable. Often mistaken for other blue gemstones, lazulite is difficult both to identify and cut. Still, the attractive blue hues of this gem make for an excellent addition to a collection.
One of the world’s rarest gemstones, gem-quality grandidierite above 2 carats is extremely rare. While most gem specimens are only translucent, a 2016 find in Madagascar is bringing more transparent material to the market. This blue-green stone is resistant to scratching but may chip if knocked or accidentally dropped. With its extreme rarity and high prices, replacing such a stone would be no easy task.
Blue Akoya Pearls
When most people think of pearls, they think of white or ivory colors. Meanwhile, aficionados have been drooling over rare blue pearls in recent years. These gems have a blue tint but the same coveted luster as white Akoya pearls. In addition, they’re much rarer. Long rejected by pearl farmers, these blue pearls have gained traction. Today, consumers are searching for something natural yet more unusual than a typical white pearl strand. However, like all pearls, blue Akoyas are soft and require special care.
Bold blue colors in azurite make it a popular stone for collectors and hobbyists. Often confused with lapis lazuli, this gem often forms with malachite, and lapidaries cut opaque blue and green cabochons from this material. Facetable crystalline material is rare, and cut gems above a carat would be too dark. Still, the intense color lends itself well to cabochons. As with any soft material, store azurite jewelry away from harder stones.
Kyanite is an unusual gem. Its hardness varies from 4 to 7.5 on the Mohs scale, depending on the crystal axis. Often a grayish blue, it also usually contains inclusions. Still, some lapidaries have managed to facet kyanite, in spite of its cleavage and designation as a brittle stone.
Certain specimens of labradorite feldspar exhibit a delightful blue sheen when properly oriented. This effect, called labradorescence, arises from twinned mineral planes. When this phenomenon covers the entire stone, the result is spectacular. With low costs and relative abundance, labradorite can be a part of any gem collection.
Sodalite is another opaque blue option for jewelry. Lapidaries often use this material for carvings, cabochons, and beads. A component of lapis lazuli, sodalite has long been treasured for its lovely color. However, it remains inexpensive, even in large sizes. With a relatively low hardness, it may scratch easily but is unlikely to break.
Sometimes known as fibrolite, due to the fibrous form in which it sometimes occurs, sillimanite can have beautiful crystals. Although fairly hard (6.5-7.5), this material is also brittle and may cleave or fracture easily. This makes it a challenge for lapidaries and a risky choice for jewelry. Though more common as a pale yellow stone, sillimanite can have pale blue hues like a light-tone aquamarine. Most dark blue specimens have been dyed.
First discovered in the Shattuck Mine in Bisbee, Arizona, this copper silicate often exhibits colors similar to turquoise. This mineral rarely grows as a large crystal form. Instead, it often pseudomorphs after malachite. While soft and brittle on its own, shattuckite often occurs mixed with quartz in a massive deposit. When this happens, the resulting gem material with bright blue and blue-green colors becomes durable enough for wear.
Blue Collector’s Gemstones
Some gems are best for display only, safe from the bumps and scratches that can arise from jewelry wear. Although these blue gemstones may not be ideal for jewelry, they can bring color and interest to a viewing collection.
Made of zinc carbonate, smithsonite is both brittle and soft. However, faceted stones can exhibit spectacular dispersion. This fire makes it highly desirable for gem enthusiasts. While this mineral can have a variety of colors, blue to blue-green material is a favorite for mineral collectors.
Vivianite is so soft, a fingernail could scratch it! Even more unusual, this mineral darkens when exposed to light. Most specimens come out of the ground colorless or with only a pale green hue. Over time, they can darken into a deep blue. In spite of the challenges vivianite poses, a few lapidaries have succeeded in cutting this gem.
Possibly the tastiest gem, halite is the mineral term for sodium chloride, best known as salt. Defects in its crystal lattice can result in spectacular royal blue and violet colors. Mineral collectors seek perfect cubic crystals. Due to its solubility, brittleness, perfect cleavage in three directions, and low hardness, lapidaries would have difficulty faceting this stone.
This zinc silicate mineral can show pale to rich blue colors. Crystalline hemimorphite is rare, but some cabochons of massive specimens exist. Some mineral specimens have microcrystalline material, and a few large, facetable crystals have been mined. However, this stone is brittle and soft, so any faceted stones may be best suited to a collection.
This iron arsenate mineral is soft and somewhat brittle, making it too fragile for jewelry wear. However, scorodite’s arsenic content may be a better reason not to wear this gem. Although not highly poisonous in its mineral state, exposing scorodite to water (such as sweat) could allow arsenic to leach out. Crystals large enough to facet do occur, though rarely. Nonetheless, lapidaries have used their skills to show off the blue colors of this dangerous mineral. If you choose to cut this stone, take precautions. Don’t inhale any dust or mist and wash your hands thoroughly.
Most often found in Pune, India, cavansite crystals can have a beautiful blue hue. However, specimens large and transparent enough to facet are extremely rare. Sometimes druzy or massive cavansite is worn as jewelry. However, these stones are soft and brittle.