Blue Sapphire
Blue Sapphire is the most precious and valuable gemstone. It is a very desirable gemstone due to its excellent color, hardness, durability, and luster. In the gem trade, Sapphire without any color prefix refers to the blue variety of the mineral Corundum. However, the term Sapphire encompasses all other gem varieties and colors of Corundum as well, excluding Ruby, the red variety of Corundum, which has its own name since antiquity.
Sapphire is one of the most popular gemstones, and is used extensively in Jewelry. Fine colored Sapphire with a deep blue color and excellent transparency can reach several thousand dollars a carat. The blue variety is most often used in jewelry, but the yellow, pink, and orange "fancies" have recently become very popular. Green and light blue Sapphires are also known, but are less commonly used in jewelry. Opaque Black Sapphire is also used a minor gemstone.
Sapphire is used in all forms of jewelry, including bracelets, necklaces, rings, and earrings. It is used both as centerpiece gemstone in pendants and rings, as well as a secondary stone to complement other gemstones such as Diamonds. Star Sapphires are polished as cabochons, and, if clear, are extremely valuable.
Chemical Formula |
Al2O3 |
Color |
White, Colorless, Blue, Green, Yellow, Orange, Brown, Pink, Purple, Gray, Black, Multicolored |
Hardness |
9 |
Crystal System |
Hexagonal |
Refractive Index |
1.76 - 1.77 |
SG |
3.9 - 4.1 |
Transparency |
Transparent to opaque |
Double Refraction |
.0008 |
Luster |
Vitreous to adamantine |
Cleavage |
None, but may exhibit parting |
Mineral Class |
Corundum |
Sapphire often contains minor inclusions of tiny slender Rutile needles. When present, these inclusions decrease the transparency of a stone and are known as silk. When in dense, parallel groupings, these inclusions can actually enhance by allowing polished Sapphires to exhibit asterism. Sapphire gems displaying asterism are known as "Star Sapphire", and these can be highly prized. Star Sapphire exists in six ray stars, though twelve ray stars are also known.
Sapphire is pleochroic, displaying a lighter and more intense color when viewed at different angles. Some pleochroic Sapphire is blue when viewed at one angle, and purple at a different angle. Color zoning, which forms from growth layers that build up during the formation of the stone, may also be present in certain Sapphires. Color zoning is responsible for certain Sapphires having lighter and darker colors in different parts of a crystal. Some Sapphire gemstones may even be multicolored such as purple and blue.
Sapphire is one of the most popular gemstones, and is used extensively in Jewelry. Fine colored Sapphire with a deep blue color and excellent transparency can reach several thousand dollars a carat. The blue variety is most often used in jewelry, but the yellow, pink, and orange "fancies" have recently become very popular. Green and light blue Sapphires are also known, but are less commonly used in jewelry. Opaque Black Sapphire is also used a minor gemstone.
Sapphire is used in all forms of jewelry, including bracelets, necklaces, rings, and earrings. It is used both as centerpiece gemstone in pendants and rings, as well as a secondary stone to complement other gemstones such as Diamonds. Star Sapphires are polished as cabochons, and, if clear, are extremely valuable.
Sources:
Important Sapphire sources include Sri Lanka, Burma (Myanmar), Thailand, Cambodia, Madagascar, Tanzania, Australia, and the U.S. (Montana). The Kashmir region of India/Pakistan was famous for its Kashmir-blue Sapphire, but little material comes from there today.
Similar Gemstones:
Iolite, blue Tourmaline, and blue Zircon may resemble blue Sapphire, but are softer. The other color varieties of Sapphire are commonly confused with many gemstones, but their great hardness can distinguish them.