Topaz is very unqiue gemstone. In Pakistan it has 2 types. One is brown topaz and one is pink Katlang topaz. Brown topaz is found in Skardu region of Pakistan. Pink Katlang is found in Mardan region of Pakistan. 

Technical Information about Topaz

Topaz Chemical formula is Al₂SiO₄(F, OH)₂. This is a silicate mineral of aluminium and fluorine. Topaz crystal structure is based in the orthorhombic system, and its crystals are mostly prismatic terminated by pyramidal and other faces.

Topaz Gemstones

Topaz crystals structure: Prismatic to Block looking with Rhomb Looking Cross section

Hardness: 8

S.G: 3.5

Colour: Brown

Luster:

Transparency: Transparent

R.I: 1.61 - 1.64

D.R: 0.009

Crystal Structure: Orthorombic

Inclusions: finger type prints pincoid cleavage