Imperial Topaz.

topaz

Imperial Topaz (aka precious topaz) is the name given to the high-quality, gem-grade variety of natural topaz with peachy-orange or reddish-orange colour tones.  It is considered to be somewhat rare and valuable.  Value and quality are dependant on the colour intensity, size, clarity of the crystal and

When topaz occurs in shades of yellow it is referred to as 'yellow' or 'golden' topaz depending on colour intensity.

Light colours

Historically and currently the world’s most important producer of imperial topaz is Brazil.  Other current mining locations include; USA, Pakistan, Sri Lanka, Russia and Mexico.

 

is naturally quite common in light brown to colourless shades; this material is usually heavily treated into the inexpensive blue topaz seen in the trade.      In the past, inexpensive citrine was sometimes called by the misnomer ‘quartz topaz’ or even just ‘topaz’ as the colour range of valuable imperial topaz is rather close to that of citrine.  Unfortunately this practice still exists in some Asian markets. 


Mohs’ Hardness: 6.5-7
Specific Gravity: 3.50-3.54
Refractive Index: 1.629-1.637
Birefringence: 0.08-0.010
Optic Sign & Character: Biaxial Positive
ICA Code: N or E
Treatments: Heating
Incidence: Common
Purpose: To drive out brown tones
Durability: Moderate to good
Special Care: Avoid hard knocks and bumps.
Synthetics: None
Possible Imitations: Glass, CZ, synthetic quartz