Turquoise is a stone used in ancient jewelry and artifacts, having been mined since at least 6000 BC by early Egyptians, and has been in fashion ever since.  The name comes from a French word, "turquoise" which means Turkish, from which country Persian material passed on its way to Europe. Turquoise is a secondary mineral found often in the weathered zone of a copper deposit.
The finest turquoise comes from Iran, but beautiful specimens are also found in the southwestern US.
Because natural turquoise is often very porous and unstable, several processes have been developed to make the material saleable.  In STABILIZATION, epoxy and plastics or water glass are impregnated under pressure into the unstable stone. In RECONSTITUTION, small fragments of turquoise material are powdered and then rebonded to form a larger solid stone.

 

 

For more information about Turquoise try these links:

http://stoneplus.cst.cmich.edu/turquoise.htm

http://minerals.usgs.gov/minerals/pubs/commodity/gemstones/sp14-95/turquoise.html

http://www.gemstone.org/index.php?option=com_content&view=article&id=135:sapphire&catid=1:gem-by-gem&Itemid=14