Blue Gemstones: A Guide to Colored Stones
When it comes to colored gemstones, color is king. Today, many customers prioritize color and are less concerned with the actual gemstone variety as long as the stone is durable enough for their purpose.
However, finding gems by color can often be very difficult especially since gemstone dealers tend to list availability by gem type or gem variety rather than by gem color. When most people think about a blue gemstone, sapphire is usually the first gemstone to come to mind, but there are a number of other blue gemstones available today.
Using our guide below, you can learn about some of the most popular blue gemstones choices available today:
Blue AgateBack to Top
Agate is a layered form of chalcedony quartz. It is known to occur in a wide variety of colors and interesting patterns, including many shades of light to dark blue. Some popular trade names used for blue agate include blue lace agate, Mohave blue agate and blue banded agate. Many agates today may have been dyed, but unlike many other gem types, the dyeing of agate does not normally affect its value. However, any such treatment should always be disclosed by gemstone traders. Agate has excellent hardness and durability, making it one of the most versatile blue gemstones today.
Blue AquamarineBack to Top
Aquamarine is a member of the beryl family and is colored by traces of iron. Its color can range from blue to bluish-green and is typically very subtle, especially when compared to more vivid and intensely colored blue gemstones such as blue topaz. Aquamarine is one of the few naturally blue untreated gemstones (although some darker stones may be heated) and it has excellent hardness and durability. It is also known to occur with rare cat's eye chatoyancy. Aquamarine is also the official modern March birthstone.
Blue ApatiteBack to Top
Apatite is composed of calcium phosphate, the same material that makes up our teeth and bones. Although it is a very common mineral, gem-quality materials are extremely rare. Apatite is the defining mineral for 5 on the Mohs scale and it is known to occur in a wide variety of colors including a 'Paraiba'-like blue-green. Apatite is normally untreated, but one variety known as 'moroxite', is routinely heated to enhance its color. Some rare apatite gemstones may exhibit cat's eye chatoyancy, known in the trade as cat's eye apatite.
Blue AzuriteBack to Top
Azurite is a rare gem-quality variety of copper ore. There are two basic copper carbonate minerals - azurite and malachite. Of the two, azurite is much rarer. Azurite has a very distinctive and vivid blue color often described as, 'azure blue', hence its name. Azure blue refers to the unique deep lapis-like color seen in fine quality azurite. Azurite may also be found mixed with malachite, forming attractive blue-green gemstones. Azurite druzy is also very popular for jewelry, and it is much more durable for wearing owed to the hardness of its matrix rock.
Blue BenitoiteBack to Top
Benitoite is a rare mineral first discovered in California by James Couch in 1907. It is a fine blue barium titanium silicate. It is one of the rarest gemstones available today. Benitoite has a higher dispersion rating than diamond and is known to display impressive brilliance and fire. Though the mineral benitoite has been found in various locations around the world, gem-quality and facetable material has only been found in San Benito, California. Benitoite is the official state gemstone for California.
Blue ChalcedonyBack to Top
Chalcedony belongs to the quartz group of minerals. Technically, 'chalcedony' is the umbrella term for all cryptocrystalline quartz. It can occur in a wide range of different colors, sizes and patterns. In the gemstone trade however, the term 'chalcedony' is typically used only to refer to 'chalcedony in the narrow sense' or 'actual chalcedony', which is the solid colored, translucent light-white to bluish gemstone. It's been recently discovered that chalcedony quartz is actually a combination of quartz and a polymorph known as moganite. Chalcedony takes an excellent polish and high quality materials can exhibit a glowing attractive luster.
Blue ChrysocollaBack to Top
Chrysocolla is a gem-quality hydrous copper silicate. It appears similar to both azurite and malachite. Although chrysocolla is most famous for its vivid blue to cyan green color, it can also be found in a wide variety of unusual and unique combinations of blue and green. Chrysocolla is colored by copper and is often confused with turquoise because of its similar color and appearance. Identifying chrysocolla by composition can be extremely difficult since it lacks a definitive chemical composition. Any blue to green copper-bearing silicate that cannot be specifically identified as something else otherwise, can essentially, be identified as chrysocolla. Most gem labs will not confidently issue identification reports for chrysocolla for these reasons mentioned.
Blue DiamondBack to Top
Diamond is the hardest known natural material on earth, rating 10 on the Mohs scale of mineral hardness. Its name comes from the Greek word 'adamas', meaning invincible. Diamond is composed of pure carbon, the same material that makes up graphite, a very common material used in the production of pencil lead and various other industries. Blue diamond is typically irradiated to obtain its color, though some very rare stones may be completely natural and untreated. Most blue diamond will exhibit a secondary greenish hue. Blue diamond is prized for its rarity, exceptional hardness, high refractive index and high dispersion rating - the ability to split white light into its component colors.
Blue Dumortierite QuartzBack to Top
Blue quartz is rare indeed, making dumortierite quartz one of the rarer varieties of quartz available. Dumortierite quartz is quartz aggregate intergrown with the mineral dumortierite. Its unusual and distinct blue color is owed to the mineral inclusions of dumortierite. Its color can range from very light to dark-blue and in some rare cases, reddish-brown. Like all quartz, dumortierite has excellent hardness and durability, making it suitable for any type of jewelry. It is also often used for the production of porcelain and ceramics, as it turns pure white when heated.
Blue FluoriteBack to Top
Fluorite is one of most popular collector's gems in the world, second only to quartz. In fact, it is often referred to as 'the most colorful mineral in the world'. Fluorite gems can be found in a variety of vivid and intense colors and patterns. Fluorite was first described in 1530 and was originally referred to as 'fluorspar'. The term 'fluorescence' came from fluorite because fluorite was one of the first fluorescent minerals studied. The fluorescent colors of fluorite are extremely variable, but the typical color is blue. Faceted fluorite is very rare, which is why most fluorite is cut en cabochon. The most valuable fluroite is known as color change fluorite; a rare variety that exhibits a noticeable change in hue when viewed under different lighting conditions, typically blue in daylight, and purple under incandescent light.
Blue Hawk's EyeBack to Top
Hawk's eye is a rare blue-gray to blue-green form of fibrous quartz. Actually, hawk's eye is a pseudomorph of quartz which began its life as another mineral - blue crocidolite. Over time, chalcedony quartz slowly replaced the original blue crocidolite mineral while retaining its fibrous form and some of its blue color, depending on the level of oxidization during its formation. Hawk's eye is also closely related to tiger's eye and pietersite. Hawk's eye is typically multicolored with golden stripes or wavy patterns and is famed for its chatoyancy, (also known as the cat's eye effect, but in the case of hawk's eye, it is considered to be a bird's eye). The chatoyancy can be seen as small rays of light reflecting off the surface of stones, even when flat-cut.
Blue HemimorphiteBack to Top
Hemimorphite is one of two rare zinc silicates formerly referred to as calamine. Hemimorphite is closely associated with another blue to blue-green gemstone known as smithsonite. For many years, both hemimorphite and smithsonite were classed together as 'calamine' because of their close resemblance and gemological properties. Hemimorphite has a hardness of 5 on the Mohs scale and can occur in various tones of blue, green and white. Most hemimorphite is blue to blue-green with a color similar to chrysocolla. Sky to Swiss blue hemimorphite is most desirable, often exhibiting bands of blue with white streaks. Although it is more of a collector's gem than a jewelry gem, with proper settings and care, hemimorphite can be used to make extraordinary gemstone jewelry. Hemimorphrite druzy is also very popular for jewelry, and is more durable owed to the hardness of its matrix rock.
Blue IoliteBack to Top
Iolite has a history that dates back hundreds of years, but the actual gemstone is considered relatively new and lesser-known. Iolite is a transparent, gemstone quality form of the mineral cordierite. It has a hardness of 7 to 7.5 on the Mohs scale, making quite suitable for jewelry-wear. Iolite is known to exhibit pronounced pleochroism, often displaying violet-blue, yellow-gray and light-blue all in the same stone, depending on the angle from which it is viewed. When cut properly, iolite is typically violet to purplish-blue.
Blue KyaniteBack to Top
Kyanite is a very unique gemstone famed for its unique coloring. Its name is derived from a Greek word for 'blue', although it can occur in a variety of other colors as well. The most desirable kyanite gemstones exhibit a sapphire-like blue color, but most stones will display noticeable light and dark color zoning, along with some white streaks or blotches. Its vitreous to pearly luster makes it a very attractive gemstone. Kyanite is also known for its distinct significant variable hardness; when cut perpendicular to the long axis it has a hardness of 6 to 7 on the Mohs scale, but when cut parallel to the long axis its hardness is only 4 to 4.5. Proper cut orientation is essential due to Kyanite's hardness.
Blue LabradoriteBack to Top
Labradorite belongs to the plagioclase group of feldspar gemstones. Its basic body color is normally dark-smoky to gray, with a remarkable metallic sheen or schiller, typically royal blue in color. Some of the finer labradorite specimens may display the full colors of the spectrum through their iridescence - these special stones are known in the trade as 'spectrolite'. Labradorite has a hardness of 6 to 6.5 on the Mohs scale, making it sufficiently hard for most jewelry use.
Blue Lapis LazuliBack to Top
Lapis lazuli - or just 'lapis' as it is affectionately known - is one of the most popular blue gemstones of all time. Its use in decorative ornamental jewelry dates back thousands of years. The finest lapis is said to originate from Northern Afghanistan, where it has been mined for over 6,000 years. Technically, lapis lazuli is defined as a rock and not a mineral. Many lapis stones may contain as many as 15 different minerals in a single stone. With lapis, the primary constituents include lazurite, calcite and pyrite. Lazurite gives lapis its vivid blue color. Calcite is a white mineral responsible for its white marbling, and pyrite lends lapis its distinctive gold speckles and glitter. Lapis is considered to be fairly soft, rating just 5 to 6 on the Mohs scale of hardness, but it is still very popular in jewelry designs.
Blue LarimarBack to Top
Larimar is the blue to green-blue gemstone variety of pectolite. The name 'Larimar' is a trademarked name. Larimar is found in only one location in the entire world - the Dominican Republic. Larimar's distinct color is owed to calcium being replaced by copper impurities. Larimar is often mixed with calcite and hematite, which can lend it very interesting shades of blue, ranging from white-blue to light-blue, and medium sky-blue to volcanic-blue. Volcanic blue Larimar is considered to be the most valuable. Larimar is rather soft, rating just 4.5 to 5 on the Mohs scale, but its use in jewelry remains quite popular. Larimar is very popular in the Caribbean, but it is extremely hard to find in any other area of the world.
Blue Moonstone & Blue Rainbow MoonstoneBack to Top
Moonstone is the best-known variety of orthoclase potassium feldspar, but 'rainbow moonstone' is technically not a true moonstone at all. Rainbow moonstone is a trade name for a special variety of labradorite, which is plagioclase feldspar that exhibits a bluish adularescence similar to the potassium feldspar moonstone. However, most consider both gem types to be one and the same for simplicity's sake. The name 'moonstone' is owed to moonstone's bluish-white shimmering effect that resembles the moon shining in the night sky. The phenomenon is known as adularescence and is a result of moonstone's unique structural pattern. Though most moonstone exhibits a bluish-white sheen, many other colors can be seen through its adularescence. Moonstone that exhibits the optical phenomena of chatoyancy is rare, but not unheard of. Chatoyant moonstone is known in the gem trade as star moonstone.
Blue SapphireBack to Top
Sapphire is the best-known blue gemstone (though it also occurs in many other colors). Sapphire's blue color can range from light-blue to deep-blue. Since sapphire is a gem-quality form of corundum, it is incredibly hard and durable, with a hardness of 9 on the Mohs scale. It is also considered to be one of the most precious of all gems available today. Some blue sapphires are known to exhibit phenomenal characteristics such as asterism (star) or color shift abilities. Today, blue sapphire from Sri Lanka (Ceylon) is considered most desirable, but previously, finds from Kashmir and Mogok, Burma, were known to be the finest quality. Blue sapphire from Cambodia (Pailin) was also known to be of distinctive purity. Many even consider Pailin sapphire to be close in quality to Kashmir, Burmese and Sri Lankan (Ceylonese) sapphire. Sapphire can also be found with phenomenal traits, such as rare color change sapphire, as well as remarkable chatoyant star sapphire. Blue star sapphire is highly sought-after and especially valuable by collectors and jewelers alike. Sapphire is also one of September's birthstones.
Blue SmithsoniteBack to Top
Smithsonite is a rare gem-quality zinc carbonate that is very closely related to blue hemimorphite, as mentioned above. Smithsonite is sometimes also referred to as 'zinc spar'. It is typically blue-green to green-blue in color and like hemimorphite, it is a very popular collector's gem, owing to its extreme rarity. Smithsonite was named after James Smithson, a highly esteemed chemist and mineralogist. The famous Smithsonian Institute was actually named after Smithson, who funded the building with a donation made through his living will. Like hemimorphite, smithsonite is rarely used in jewelry owing to its rarity, but with care and proper design, smithsonite can make stunning wear.
Blue SodaliteBack to Top
Sodalite is a vivid blue gemstone that gets its name from its high sodium content. Sodalite's color is typically very deep blue, similar to lapis lazuli. It also often exhibits interesting white veins or patches that are due to calcite inclusions. Sodalite is sometimes traded as 'alomite' or 'ditoite'. Hackmanite, an exceptionally rare variety of sodalite, is known to exhibit a rare color change phenomenon known as reversible photochromism or 'tenebrescence'. Unlike other color-change gems, this rare form of sodalite can fade in color to grayish or greenish-white when exposed to sunlight, and when placed in the dark for an extended period of time, it will revert to its original color.
Blue SpinelBack to Top
For many centuries, blue and red spinel was mistaken for blue sapphire and red ruby. Spinel has very similar gemological properties to sapphire and ruby, which are both forms of corundum. Like corundum, spinel can also occur in a wide variety of colors. Some spinel colors are considered rarer and more valuable than others. In general, fine red spinel is considered to be the most valuable, followed by rare blue spinel. Cobalt-blue is the most desired shade of blue spinel. Like diamond, spinel is singly refractive, resulting in very pure color. The best blue spinel should have medium to medium dark color, similar to fine blue sapphire. Unlike sapphire, blue spinel is typically never treated in any way. Spinel is just slightly softer than sapphire, but it is still considered very hard and durable. Therefore it is perfectly suitable for any type of jewelry application.
Blue TanzaniteBack to Top
Tanzanite is one of today's most popular gemstones. It is an intense violet-blue gemstone variety of zoisite found in only one location in the entire world - the Merelani District of Tanzania near Mount Kilimanjaro. Tanzanite's vivid and distinct violet-blue color is like no other gemstone color available, but like many blue gemstones, tanzanite obtains its radiant color through routine heat-treatment. Tanzanite is slightly soft when compared to many other types of jewelry gemstone (6 to 7 on the Mohs scale), but it is still hard enough for most jewelry. Tanzanite is the newest gemstone to make it on the AGTA's modern birthstone list as one of December's birthstones.
Blue TopazBack to Top
Blue topaz is the second most popular colored gemstone of all time (according to Colored Stone magazine, sapphire is number one). Blue topaz has a hardness rating of 8 on the Mohs scale and is considered to be one of the most affordable gemstones. Like many gemstones today, the radiant blue shades of topaz are obtained through an artificial irradiation and enhancement process. The colors of blue topaz are generally classed as three different 'levels' or shades; London blue topaz is a rich deep blue topaz, which is considered to be the most valuable and desirable shade of blue. A medium blue known as Swiss blue Topaz is second most popular, followed by a light sky-blue topaz. Blue topaz is also recognized as one of December's official birthstones.
Blue TourmalineBack to Top
Blue tourmaline is the general term applied to two rare varieties of tourmaline: Paraiba tourmaline and indicolite tourmaline. Pure blue tourmaline is exceptionally rare, since most blue tourmaline exhibits a noticeable secondary green hue. Paraiba tourmaline is considered to be the most valuable variety of tourmaline and was named after the locality of its original discovery in Brazil. Paraiba tourmaline obtains its neon green-blue color through traces of copper. Technically, the term 'indicolite' can be used to describe any other form of blue tourmaline. Indicolite's color can range from light to deep-blue. Any blue tourmaline is considered to be very rare and anything over 1 carat is especially rare. Tourmaline is both hard (7 to 7.5 on the Mohs scale) and durable. Tourmaline with cat's eye chatoyancy isn't all that rare, but they are difficult to find. Cat's eye tourmaline is highly sought after by collectors. Tourmaline is also October's birthstone.
Blue TurquoiseBack to Top
Turquoise is one of the best-known gemstones. In fact, the color 'turquoise' was named after the gemstone and not the other way around. Pure blue turquoise is quite rare. Like many blue gemstones, turquoise will typically have a noticeable touch of green. Many turquoise gemstones are greener than they are blue. A sky-blue turquoise with minimal veining is typically considered to be the most valuable, though in some countries, blue turquoise with black veins or complex matrix patterns are more desirable. The blue in turquoise comes from traces of copper, and green comes from traces of iron. Although turquoise is rather soft compared to many other jewelry gemstones (5 to 6 on the Mohs scale), it is very often used in jewelry. Turquoise is one of December's birthstones. Untreated turquoise is becoming increasingly rare. Most turquoise today has been enhanced through dying, waxing, impregnation or stabilization.
Blue ZirconBack to Top
Blue zircon is the most brilliant blue gemstone available. It has a higher refractive index than sapphire, tanzanite and spinel, and blue zircon also possesses a very high level of dispersion; the splitting of white light into the spectral colors. Zircon is considered to be reasonably hard (7 to 7.5 on the Mohs scale) though it can be brittle, resulting in facet edges wearing down over time. As a result of pleochroism, blue zircon often exhibits a slight greenish hue. Although zircon is a natural mineral, blue zircon is produced by the heating of brownish zircon from Cambodia and Myanmar (Burma). Zircon stones should never be mistaken for the artificial, synthetic diamond simulant known as cubic zirconia (CZ) that is not related to natural zircon.
- First Published: June-09-2014
- Last Updated: October-12-2017
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