Topaz has hardness of 8 Mohs. It is formed of aluminum silicate fluoride hydroxide and its specific gravity is 3.5 - 3.6.
The Egyptians said that topaz was colored with the golden glow of the mighty sun god Ra. This made topaz a very powerful amulet that protected the faithful against harm. The Romans associated topaz with Jupiter, who also is the god of the sun. Topaz sometimes has the amber gold of fine cognac or the blush of a peach and all the beautiful warm browns and oranges in between. Some rare and exceptional topaz is pale pink to a sherry red. It is available in wine yellow, pale blue, green, violet, or red.
Nature rarely produces Topaz in the blue variety, although some examples have been found. Challenged by this rare occurrence of nature, man has discovered an enhancement method to "excite" blue color from a clear to brownish Topaz variety. After the raw Topaz is mined, it is irradiated to brown and then heated to a rich sky blue. This enhancement process is permanent.