Topaz is a hard crystal that comes in a variety of colors.

Chemical Formula: Al2SiO4(F1OH)2
Class: Silicates, Mesosilicates
Hardness: 8
Coloration: Colorless, blue, yellow, pink, brown.

How to identify it/Unique Characteristics or Properties: Topaz is a hard crystal that has been used as a gemstone for centuries. It comes in a variety of colors, but the classic color is a yellow/orange. The clear can be mistaken for a diamond it is so brilliant when cut well, but it is the rare pinks and blues that are the most valuable. However, since the color can be changed by heat treatment, most topazes today have been augmented. The color can fade in the sun, and the crystals can be identified in its natural state by a lozenge shaped cross section.

Where to find it in…

The Northwest: Northern Idaho and Eastern Washington
Other: Brazil is famous for its topaz, as is Egypt, Germany, and Sri Lanka
Past Uses: Jewelry is pretty much the only use of this stone.
How it was Made: The crystals form best in limestone which is in contact with granite. It requires high pressure.
Interesting Facts: Topaz was probably not known in ancient times, and what was called topaz was probably peridot.