SMOKY QUARTZ

 This is a natural untreated cognac colour stone.It has been cut with a checkerboard back and a flat top [called bluff cutting.]This gives a nice reflection of the cut behind it.

Grading:VS

Weight 14.7 cts app

Size 20x 15x7 mm app

Smoky quartz is a popular variety of quartz. It has an unusual color for a gemstone and is easily recognized and is well known by the general public. Only a few other brown or black minerals are ever cut for gemstones such as black diamond, smoky topaz, the very rare black beryl or brown corundum. .

Smoky quartz, a variety itself of quartz, has a few varieties of its own.

• Cairngorm is a variety that comes from the Cairngorm Mountains in Scotland.
• Morion is a very dark black opaque variety of smoky quartz.
• Coon tail quartz is a smoky quartz with an alternating black and gray banding.
• A Gwindel is a smoky quartz cluster of nearly parallel crystals, each rotated slightly relative to the one beside it.

The color of smoky quartz is variable from brown to black and sometimes smoky gray colored specimens are included as smoky quartz. The cause of the color of smoky quartz is in question but it is almost certainly related to the amount of exposure to radiation that the stone has undergone. Natural smoky quartz often occurs in granitic rocks which have a small but persistent amount of radioactivity