Honey yellow. Fiery orange. Cyclamen pink. Icy blue. In warm or cool tones, topaz is a lustrous and brilliant gem.
Topaz actually has an exceptionally wide color range that, besides brown, includes various tones and saturations of blue, green, yellow, orange, red, pink, and purple. Colorless topaz is plentiful, and is often treated to give it a blue color. Topaz is also pleochroic, meaning that the gem can show different colors in different crystal directions
BIRTHSTONES & ANNIVERSARIES
Precious topaz is a birthstone for Novemberand blue topaz is a birthstone for December. Blue topaz is the gem of the 4th anniversary and Imperial topaz is the gem of the 23rd anniversary.
The royal court in Portugal celebrates the discovery of Imperial topaz in 1768.
A transparent topaz crystal discovered in Minas Gerais, Brazil weighs an astounding 596 pounds.
Irradiating colorless topaz with electrons at energy of 10 million electron volts creates a sky blue color.
- Mineral: Topaz
- Chemistry: Al2(F,OH)2SiO4
- Color: Yellow, orange, brown, pink to red to purple red, blue , light green and colorless
- Refractive index: 1.619 to 1.627
- Birefringence: 0.008 to 0.010
- Specific gravity: 3.53
- Mohs Hardness: 8
Topaz comes in a variety of colors from shades of blue to the rare reddish imperial colors.
The most valued topaz colors are orangy red to red. Blue gems are widely available.
Topaz used in jewelry is typically eye clean with no visible inclusions.
Topaz crystals are usually columnar, and cut as oval or pear shapes to improve yield.
Topaz often forms as large crystals. These can yield sizable cut gems.