text-align:justify Ruby and sapphire are different color varieties of the same mineral, corundum. Ruby is the red variety, while sapphire is any color variety
other than red, and so is preceded by its color designation (i.e., “Blue Sapphire” or “Yellow Sapphire”). The name “Ruby” originates from the Latin ruber, for red, but this term fails to convey the hypnotic quality of a fine ruby’s fiery depths. The finest rubies come from Burma (also known as Myanmar), where they have been mined for centuries. Other localities include Vietnam, Thailand, India, Afghanistan and Tanzania.
Ruby is very hard, second only to diamond, and is safely worn in rings as well as other forms of jewelry. The cause of ruby’s legendary color is chromium, usually combined with some iron in trace amounts in the chemical structure of the ruby. Ruby occurs much more rarely than sapphire and, therefore, brings higher prices on average. Rubies weigh over 3 carats are extremely rare and can command high prices. A star ruby forms when microscopic needle-like inclusions of rutile crystals align in a three-fold symmetry and create a star on the surface of a cabochon cut stone.
Famous rubies include the 167 carat Edwards ruby in the British Museum of Natural History; the Smithsonian Institute’s 138.7 carat Rosser Reeves star ruby, which is one of the finest star rubies in existence; and the 100 carat DeLong star ruby in the American Museum of Natural History. In 1986, a 15.97 carat cushion shape ruby named “Alan Caplan’s Ruby” or the ”Mogok Ruby” was auctioned by Sotheby’s for $3,630,000 or $227,301 per carat.
Variety: Ruby, star ruby
Chemical Composition: Al2O3
Color: Red, violetish-Red, pinkish-Red, brownish-Red
Crystal System: Hexagonal
Refractive Index: 1.762 - 1770 (+.009, -.005)
Specific Gravity: 4.00 (+/- .05)
Images by Jack Abraham.