Red is one of the most sought-after topaz colors and represents less than one-half of 1 percent of facet-grade material found. The color the trade calls imperial topaz is highly prized and very rare.

The blue color produced by irradiation and subsequent heat treatment is stable to light. Currently, no routine gemological tests are available that can definitively determine whether the color of the ...

Topaz, known for its durability and variety of colors, plays a significant role in the world of gemstones. "Topaz is chosen ...