Gemstones - Precious Gems
Zircon
Over the years, zircon has been a much maligned and misunderstood gemstone because of its use as a diamond substitute and sometimes involved in fraudulent transactions.
With a high refractive index and high dispersion coupled with a near adamantine luster, zircon makes an extremely attractive gem.
But zircon does have two weaknesses.
- The natural radioactive decay of uranium and thorium within zircon which damages the crystal lattice and may cause the gem to lose their structure, to become amorphic. The condition is referred to as "metamict". The crystals may become dark and cloudy.
- The gems brittleness is another reason to be cautios when considering for purchase. Abraded and damaged facet junctions are common on Zircon.
On the plus side, zircon occurs in virtually color and produces some beautiful gems in natural blues, oranges, greens and yellows.
Properties of Zircon
- Crystal System - Hexagonal
- Hardness - 9
- Specific Gravity - 3.99 to 4.0
- Refraction - Double
- Refractive Index - 1.757 to 1.779
- Dispersion -
- Birefringence -
- Wearability - Excellent
- Special Care - None