Sapphire is thought to make the melancholy cheerful and maintain the power or vigor of the body. The stone helps the eyes, boils, rheumatism, and colic. The high priest of Egypt wore a sapphire upon his shoulder, and Aelian says that it was called truth.
Sapphire refers to the gemstone in its pure form or it may refer to green chrysoberyl when green beryl (emerald) replaces red beryl (ruby). When used in pieces of jewelry, it’s typically colorless. But corundum existing in different colors are referred to as sapphires with colors like pink, yellow, orange and purple. All these colors come from impurities trapped in the crystal structure, so they have the same chemical composition which is aluminum oxide [Al 2 O 3 ] .
Light transmission measurements show that a piece of blue sapphire transmits 97% while a piece of ruby only 69%. This can be attributed to a difference in refractive index. As seen in the picture below, red light is refracted away from the normal when entering sapphire while it’s partially reflected once it hits ruby.
Blue sapphire has a very high relief factor of 46% while ruby only 26%. This means blue sapphire will appear much more brilliant under direct lighting.
The Buddhists still ascribe a sacred magical power to it, and hold that it reconciles man to God. The sapphire is a good amulet against fear, promoting the flow of animal spirits, hindering argue and gout, promoting chastity, and preventing eyes from being affected by smallpox. (see Gem Healing) A.G.H.