The first blue gemstone to come to mind is usually sapphire, but there are plenty of options. Explore ten different types on our blue gemstone list.
Blue Gemstone Names
Blue is a calming color that is often associated with wisdom and loyalty. Though the color is rarely found in food, it makes up most of the sky and ocean. A favorite of most, this color captivates its audience with its serene nature. It’s no surprise then that blue gemstones are popular sellers for fine jewelry and engagement rings.
The most common and well-known type of blue gemstone is blue sapphire, which is one of the few precious gemstones on the market.
Sapphire can rival diamonds in both cost and beauty. However, if you’re limiting your jewelry search to only blue sapphires, you’ll be missing out on a lot of other remarkable blue gemstones.
Explore our slideshow for some rare and unusual blue gemstones you probably never knew existed. You may even find a new favorite.
1. Blue Fluorite
- Composition: Calcium Flourite, CaF2
- Mohs Scale of Hardness: 4
Fluorite crystals have been prized for their unique cubic structure as far back as the ancient Egyptians but were officially discovered in 1530 as fluorspar. In its pure chemical form, fluorite is colorless. However, certain impurities within the stone can turn it into pretty much any color in the rainbow. The name comes from the Latin word fluor which translates as “flow of water.”
Among the most interesting and beautiful blue rocks and gems, fluorite has long been sought after by collectors and enthusiasts alike. Historically, it hasn’t been particularly popular in jewelry or decoration which can make a very interesting statement piece. So few people have seen fluorite in person that it’s bound to get their attention and attract questions.
In 1852, the term fluorescence was named after this crystal due to the high presence of this optical phenomenon in many fluorite stones. Fluorescence describes the ability of these and other crystals to absorb light then send it back to the eye in the form of a glowing color change. Fluorite often presents this change of color in a stunning blue or violet light.
Since the stone is so soft, fluorite is mostly incorporated into crystal healing or used as a decorative object. However, since the stone is so beautiful, it has been incorporated into jewelry as well.
If you’re buying blue fluorite jewelry, search for stones that are bezel set. The bezel settings protect the edges of this soft stone from chipping. Most gem-quality fluorites stones will have excellent transparency and should lack visible inclusions. Despite its beauty and ability to be transformed into jewelry, it should be worn sparingly and with great care.
2. Blue Iolite
- Composition: Magnesium Iron Aluminium Cyclosilicate, Mg2Al4Si5O18
- Mohs Scale of Hardness: 7-7.5
Coined as the “Water Sapphire,” Iolite gets its unique blueish-purple color from the presence of iron. Though the gemstone has been around for hundreds of years, it is still considered a relatively new discovery. Its color can rival even the finest tanzanite gems without the exorbitant price tag. Iolite gets its name from the Greek word ios, meaning “violet.” This rich blue gemstone is pleochroic, which means that it will disperse its colors differently depending on the angle you view the stone in relation to a light source.
To maximize the value of iolite, seek a stone that is between 2-3 carats. Stones that are larger than this are significantly rarer and harder to find. Iolite is usually left untreated, making it a great option for buyers that value 100% natural gemstones.
3. Blue Dumortierite Quartz
- Composition: Silicon Oxygen, SiO and Aluminium Boro-Silicate, Al7BO3(SiO4)3O3
- Mohs Scale of Hardness: 7
Dumortierite is a blue mineral that is rarely ever found on its own. The crystal was originally discovered in 1881 and usually forms within quartz gemstones in the form of inclusions. When dumortierite is present, these inclusions turn quartz a rare shade of blue and create what is known as blue quartz or “dumortierite quartz.” Quartz is abundant, with rose quartz being its most popular and well-known variety.
Dumortierite quartz, on the other hand, is rare and much more difficult to source.
This stone is meant to be appreciated for its inclusions. Transparent cabochon-cut gems like the one shown here highlight the fibrous nature of dumortierite and work well in high-end jewelry designs. Quartz is known for its durability, and this variety is no different. Expect jewelry pieces made with dumortierite to withstand the test of time with proper care.
4. Blue Kyanite
- Composition: Aluminum silicate, Al2SiO5
- Mohs Scale of Hardness: 4.5-7, depending on the cut
Kyanite comes from the Greek word kuanos, meaning “deep blue.” This stone is most prized for its sapphire blue color but is not limited to this shade. Like some sapphires, many blue kyanite stones will exhibit color zoning. This means that there may be light and dark zones throughout the stone, which is not always a desirable quality.
The most important aspect to consider when purchasing a kyanite gemstone is the quality of the cut. Cutting kyanite takes a skill. Often, gem cutters will have to balance between creating even coloring and maximizing the stone’s hardness. Stones cut properly can yield up to a 7 on the Mohs Scale of Hardness, which is considerably more durable than if not cut properly.
5. Blue Rainbow Moonstone
- Composition: Sodium Calcium Aluminium Silicate, NaAlSi3O8 to CaAl2Si2O8
- Mohs Scale of Hardness: 6 – 6.5
Blue rainbow moonstone has a cool light that seems to glow from within, but this gem actually isn’t moonstone at all. This feldspar mineral is actually a member of the labradorite family of gems. The blue tones within the gem come from an optical phenomenon known as adularescence. The stone is often referred to as moonstone instead of labradorite because moonstones are known to have adularescence.
The overall body tone on rainbow moonstone is often very faint.
Transparent stones are more valuable than opaque rainbow moonstones. Expect to see a lot of inclusions within the gemstone, especially in larger sizes. Don’t be put off by the inclusions; however, These inclusions play a large role in the glowing blue sheen.
6. Blue Azurite
- Composition: Copper Carbonate Hydroxide, Cu3(CO3)2(OH)2
- Mohs Scale of Hardness: 3.4 – 4
Azurite comes from the Persian word lazhward, meaning blue, and is formed through the oxidation of copper ore. Though this stone is similar to malachite, it is significantly rarer. Gem-quality azurite is even rarer. Most people who seek azurite stones are collectors who purchase mineral specimens. Despite its rarity, the mineral has been used as far back as the Middle Ages for dyes and pigments.
Whether used in pottery, paint, or jewelry, the stone is highly prized for its azure blue coloring.
Like many other opaque gem varieties, azurite is often carved into ornamental stones and figures. Due to the stone’s softness, it is best to find jewelry that has been bezel set. The bezel setting will protect the edges of the stone from chipping or cracking. Be sure to take care not to scratch the surface of your azurite stone by storing separately from other jewelry. Be careful not to confuse azurite with similar blue gems like lapis lazuli and sodalite.
7. Blue Spinel
- Composition: Magnesium Aluminum Oxide, MgAl2O4
- Mohs Scale of Hardness: 7.5-8
Both blue and red spinel has been mistaken for sapphire and ruby respectively for thousands of years. Even the crown jewels had red “rubies” that ultimately turned out to be spinel. Because spinel is rarer than other gemstones, it isn’t marketed much by the fine jewelry industry and isn’t as well-known as gems that are more readably available.
The hardness and durability of spinel make it an incredible choice for jewelry. Often underrated in the trade, spinel offers a wide variety of colors with intense fire similar to a diamond. However, natural blue spinel is rarer than blue sapphire, which makes it less well known and, in some cases, more expensive. One great aspect about blue spinel, when compared to blue sapphire, is that it is never heated or treated.
8. Blue Diamond
- Composition: Carbon, C
- Mohs Scale of Hardness: 10
Perhaps the most well-known blue diamond is the Hope Diamond at the Smithsonian. While diamonds come in all colors, natural blue diamonds are extremely rare. Different environmental factors and inclusions can result in diamonds turning a different color. In nature, the presence of a boron can turn a diamond blue.
There are treatments out that will turn low-grade diamonds into colors ranging from blue to green to yellow.
The color of a treated blue diamond tends to look more like a peacock blueish green.
9. Blue Indicolite Tourmaline
- Composition: Varied
- Mohs Scale of Hardness: 7 – 7.5
Indicolite tourmaline is a term used to describe any variety of tourmaline that has a blue color. Tourmaline is one of the most complexes of all gemstones because each variety is made up of various minerals. Its name comes from the Sinhalese term tura mali, meaning many colors.
Don’t expect to find an internally flawless blue tourmaline gemstone.
Most of them will have some inclusions. Be prepared to spend because blue tourmaline varieties are among the most expensive of all tourmaline stones.
10. Blue Benitoite
- Composition: Barium Titanium Silicate, BaTiSi3O9
- Mohs Scale of Hardness: 6 – 6. 5
Benitoite made our list of the rarest gemstones in the world. Why? Because it’s one of the rarest gemstones that are available. Gem-quality material has only been found in one place in Benito, California. When compared to a diamond, benitoite actually disperses light at a higher rate, creating more fire and brilliance.
The stone was first mistaken for a variety of spinel until it was reclassified in 1907.
You will need to be sure you are buying from a highly reputable dealer that specializes in rare gems and specimens when buying benitoite.