About Turquoise:

What once was regarded a common byproduct of copper mining is now realized to be a rather scarce gem.  Typically found in or near copper mines around the world, turquoise from each locality differs in color, quality, character, and rarity.  Certain mines are known for producing highly valuable material in very limited quantity.  Inclusions of other copper-bearing minerals such as azurite, malachite, and chrysocolla are not uncommon.

  Turquoise ranks 5 to 6 on the Mohs scale of hardness.  Because this is often not suitable for everyday wear, most turquoise on the market is hardened (or "stabilized") with electricity and/or polymer.  Stabilization is viewed as an accepted, regular practice in the lapidary industry and is not to be confused with "dying" material.  Dyed (or artificially colored) material is not viewed as favorably among dealers and collectors.  It is very important to be careful when cleaning your turquoise jewelry.  Turquoise is a porous stone that can absorb any harsh chemical used.  Avoid putting your turquoise jewelry in chemical jewelry cleaners, and be sure to focus only on cleaning the metal around your stone.