Topaz occurs in a range of different colors deep golden yellow topaz(sometimes called sherry topaz) and pink topaz are the most valuable; blue and green stones are also popular. Natural pink stones are rare most pink topaz is heat-treated yellow material. colorless heat treated to a range of blues, some almost indistinguishable from aquamarine when seen with the naked eye. Some topaz has tear-shaped cavities, containing a gas bubble or several immiscible(non- mixing) liquids. Other inclusions such as cracks, streaks, and veils also occur. Prismatic topaz crystals have a characteristic lozenge- shaped cross-section and striations parallel to their length. Topaz has one perfect cleavage.
|Colour||Yellow, orange, brown, pink to red to purple red, blue , light green and colorless|
|Refractive Index||1.62 to 1.63|