September – SAPPHIRE
| CHEMICAL COMPOSITION | Al2O3 |
|---|---|
| CUBIC CRYSTAL SYSTEM | |
| REFRACTIVE INDEX | 1.762-1.770 (+.009, -.005) |
| HARDNESS | |
| SPECIFIC GRAVITY | 4.00 (+.10, -.05) |
| DISPERSION | .018 |
| CLEAVAGE | none; may show parting on twinned stones |
| GIA GRADING |
Additional Information
Green Sapphire: blue-green through yellow-green; tones 2-8; saturations 1-3. Orange sapphire: yellowish orange through orangey red; tones 2-8; Yellow Sapphire: greenish yellow through orangey yellow; tones 2-4; saturations 1-5. Pink Sapphire: Red through purple; tones 2-5; saturations 1-6. Plum Sapphire: red through bluish purple; tones 5-8; saturations 1-6
Named after the Greek word "sapphirus", meaning blue, Sapphires have long been a favorite among priests and kings, who considered them symbolic of wisdom and purity. These gemstones are prominent among the British Crown Jewels, and Prince Charles chose this as the engagement stone for his fiancée, Princess Diana. More recently the ring was given to Catherine Middleton as an engagement ring by their son Prince William.
Sapphire is a variety of the mineral corundum. Corundum is found in every color of the rainbow, with red being designated as ruby, another gemstone. The most prized color of Sapphire is a rich, deep blue. They are found in Sri Lanka, Kashmir, Myanmar, Thailand, Australia, Nigeria, Kenya, Tanzania, China, Madagascar, and the United States.
Large specimens of Corundum crystals are rare, although the 563-carat Star of India can be seen in the American Museum of Natural History. This is the largest and most famous of star Sapphires, which are cut to reflect light from inclusions within the stone, revealing a bright six-legged star pattern. The Sapphire is second only to the Diamond in hardness, making it a durable gemstone for setting into jewelry. A gift of Sapphire represents sincerity and faithfulness.
Sapphires are commonly worn as jewelry. Sapphires can be found naturally, by searching through certain sediments (due to their resistance to being eroded compared to softer stones), or rock formations, or they can be manufactured for industrial or decorative purposes in large single-crystal synthetic ingots. Because of the remarkable hardness of sapphires, they are used in some industrial applications, including infrared optical components, such as in scientific instruments; high-durability windows; wristwatch crystals and movement bearings; and very thin electronic wafers, which are used as the insulation for integrated circuits.
Blue sapphires are evaluated based upon the purity of their primary hue. Purple, violet, and green are the most common secondary hues found in blue sapphires. Violet and purple can contribute to the overall beauty of the color, while green is considered to be distinctly negative. Blue sapphires with up to 15% violet or purple are generally said to be of fine quality. Blue sapphires with any amount of green as a secondary hue are not considered to be fine quality. Gray is the normal saturation modifier or mask found in blue sapphires. Gray reduces the saturation or brightness of the hue and therefore has a distinctly negative effect. The color of fine blue sapphires can be described as a vivid medium dark violet to purplish blue.
Appearance:
Misnomers: Aquamarine or aquamarine sapphire – light greenish blue sapphire. Fancy Sapphires: Oriental topaz, king topaz, imperial topaz – yellow sapphire; Oriental emerald – green sapphire; Oriental Amethyst – purple sapphire.
Typical Size Range: melee to 5 ct; faceted stones of several hundred carats occur
Typical Cutting Styles: faceted, cabochons
Cleaning Methods:
More about fancy sapphires
References
Gemological Institute of America, GIA Gem Reference Guide 1995, ISBN 0-87311-019-6
GIA. (n.d.). GIA Grading and Reports. Retrieved July 29, 2011, from Gemological Institute of America:
http://gia4cs.gia.edu/cm/grading-reports.htm
ICGA. (n.d.). All About Gems. Retrieved July 30, 2011, from International Colored Gemstone Association:
http://www.gemstone.org/index.php?option=com_content&view=section&layout=blog&id=1&Itemid=69
IGS. (n.d.). IGS Reference Library. Retrieved July 29, 2011, from Internatonal Gem Society:
http://www.gemsociety.org/info/info.htm
Named after the Greek word "sapphirus", meaning blue, Sapphires have long been a favorite among priests and kings, who considered them symbolic of wisdom and purity. These gemstones are prominent among the British Crown Jewels, and Prince Charles chose this as the engagement stone for his fiancée, Princess Diana. More recently the ring was given to Catherine Middleton as an engagement ring by their son Prince William.
Sapphire is a variety of the mineral corundum. Corundum is found in every color of the rainbow, with red being designated as ruby, another gemstone. The most prized color of Sapphire is a rich, deep blue. They are found in Sri Lanka, Kashmir, Myanmar, Thailand, Australia, Nigeria, Kenya, Tanzania, China, Madagascar, and the United States.
Large specimens of Corundum crystals are rare, although the 563-carat Star of India can be seen in the American Museum of Natural History. This is the largest and most famous of star Sapphires, which are cut to reflect light from inclusions within the stone, revealing a bright six-legged star pattern. The Sapphire is second only to the Diamond in hardness, making it a durable gemstone for setting into jewelry. A gift of Sapphire represents sincerity and faithfulness.
Sapphires are commonly worn as jewelry. Sapphires can be found naturally, by searching through certain sediments (due to their resistance to being eroded compared to softer stones), or rock formations, or they can be manufactured for industrial or decorative purposes in large single-crystal synthetic ingots. Because of the remarkable hardness of sapphires, they are used in some industrial applications, including infrared optical components, such as in scientific instruments; high-durability windows; wristwatch crystals and movement bearings; and very thin electronic wafers, which are used as the insulation for integrated circuits.
Blue sapphires are evaluated based upon the purity of their primary hue. Purple, violet, and green are the most common secondary hues found in blue sapphires. Violet and purple can contribute to the overall beauty of the color, while green is considered to be distinctly negative. Blue sapphires with up to 15% violet or purple are generally said to be of fine quality. Blue sapphires with any amount of green as a secondary hue are not considered to be fine quality. Gray is the normal saturation modifier or mask found in blue sapphires. Gray reduces the saturation or brightness of the hue and therefore has a distinctly negative effect. The color of fine blue sapphires can be described as a vivid medium dark violet to purplish blue.
Appearance:
- Sapphire varieties: green, yellow, orange, pink, purple, violet, brown, black, gray, colorless.
- Transparent to opaque
- Phenomena: asterism (star ruby, star sapphire), chaoyancy (very rare), color change (from blue to purple)
Misnomers: Aquamarine or aquamarine sapphire – light greenish blue sapphire. Fancy Sapphires: Oriental topaz, king topaz, imperial topaz – yellow sapphire; Oriental emerald – green sapphire; Oriental Amethyst – purple sapphire.
Typical Size Range: melee to 5 ct; faceted stones of several hundred carats occur
Typical Cutting Styles: faceted, cabochons
Cleaning Methods:
- Ultrasonic: usually safe
- Steamer: usually safe
- Warm soapy water: safe
More about fancy sapphires
References
Gemological Institute of America, GIA Gem Reference Guide 1995, ISBN 0-87311-019-6
GIA. (n.d.). GIA Grading and Reports. Retrieved July 29, 2011, from Gemological Institute of America:
http://gia4cs.gia.edu/cm/grading-reports.htm
ICGA. (n.d.). All About Gems. Retrieved July 30, 2011, from International Colored Gemstone Association:
http://www.gemstone.org/index.php?option=com_content&view=section&layout=blog&id=1&Itemid=69
IGS. (n.d.). IGS Reference Library. Retrieved July 29, 2011, from Internatonal Gem Society:
http://www.gemsociety.org/info/info.htm
