Sapphire
Sapphire is a type of the mineral corundum, an aluminium oxide (Al2O3). Sapphires are the same as rubies, except that they are not red.
| Sapphire | |
|---|---|
 The 422.99-carat Logan sapphire | |
| General | |
| Category | Oxide mineral |
| Formula (repeating unit) | aluminium oxide, Al2O3 |
| Identification | |
| Color | Every color except for red – which is called a ruby – or pinkish-orange (the padparadscha) |
| Crystal habit | massive and granular |
| Crystal system | Trigonal Symbol (32/m) Space Group: R3c |
| Cleavage | none |
| Fracture | conchoidal, splintery |
| Mohs scale hardness | 9.0 |
| Luster | vitreous |
| Streak | white |
| Specific gravity | 3.95–4.03 |
| Optical properties | Abbe number 72.2 |
| Refractive index | nω=1.768–1.772 nε=1.760–1.763, Birefringence 0.008 |
| Pleochroism | Strong |
| Melting point | 2030–2050 °C |
| Fusibility | infusible |
| Solubility | Insoluble |
| Other characteristics | coefficient of thermal expansion (5.0–6.6)×10−6/K |
Sapphire can be found in the ground or it can be made in large crystal. Blue sapphires are the most famous kind, but they can be many different colors, like amber and orange.
Sapphires have a long history. Tradition says that the tablets of the Ten Commandments were made of sapphire, so strong a hammer could not break them, and would break instead if it hit them. The ancient Persians believed that the earth sat on a big sapphire and that the big sapphire made the sky blue.
A lot of ancient people thought rubies made people calm down, as well as cure their bruises.
Sapphires have been used by kings and queens for a long time as a symbol of luck, virtue, wisdom, and holiness. Princess Diana and Princess Anne both received sapphire engagement rings and the British Crown Jewels are full of large blue sapphires, the symbol of kind and wise rulers.
Sapphires represent September. It symbolizes telling the truth and doing what you said you would.
Sapphire is actually just corundum and is one of the hardest minerals on the hardness scale. Since sapphire is the second hardest mineral in the hardness scale, it is sometimes used as a polishing tool.
This mineral is found in gem gravel deposits. These deposits are formed from the heat of metamorphic or igneous rock plateaus. The places where sapphire is formed abundantly are Myanmar, Thailand, India and Sri Lanka. The most costly and beautiful sapphires are shipped from Kashmir, India. In other words, sapphire is mostly found in Asia. Recent findings of sapphire have taken place in Australia, Kenya, and Tanzania.
Sapphire was the first mineral to be lab grown in a strategy called "flame fusion". Another strategy, slightly harder to use, "flux growth" was used to lab grow sapphire.
Heating yellow, light yellow, or colorless sapphire from 1500-1900oc can turn into a dark yellow, gold, golden brown, orange, or a reddish brown colored sapphire. There is a specific kind of sapphire called Star sapphires have whitish pieces of rutile or silk as some call it. Star sapphires can be heated to remove the blue color of sapphire and can be heated even more to get the blue color back and remove the white silk.
Sapphire Media
Main sapphire-producing countries
An uncut, rough yellow sapphire found at the Spokane Sapphire Mine near Helena, Montana
Teardrop-shaped blue sapphire
Dark blue sapphire, probably of Australian origin, showing the brilliant surface luster typical of faceted corundum gemstones.
Pink Sapphire ring
Padparadscha sapphire
Star sapphire cabochon displaying six-ray asterism.
68 carat star sapphire in round mogul cut - men's ring version - 750 yellow gold - Russian goldsmith - handmade around 1990
Crystal structure of sapphire
Sapphire ring made c. 1940
References
U of Texas. "corundum." ruby and sapphire notes. U of Texas, 24 Aug. 2012. Web. 30 Oct. 2012. <http://www.geo.utexas.edu/courses/347k/redesign/gem_notes/ corundum/corundum_triple_frame.htm>.
Gait, Robert I. "Sapphire." World Book Advanced. World Book, 2012.Web. 4 Dec. 2012.