Sapphire

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 is a type of the mineral corundum, an aluminium oxide (Al₂O₃). Sapphires are the same as rubies, except that they are not red.

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.

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.