Tuesday, June 1, 2010

Gemstone of the Week- Turquoise

That heavenly blue-green of turquoise evokes many images: blue skies of the American Southwest, a Caribbean sea, or a lovely robin's egg.  But it is a stone that needs some love because it has been fiddled with for too long and most people don't know if they are truly looking turquoise when they see it.  Why is that?  Well, turquoise has many imitators, such as howlite and magnesite (both normally white) that can be dyed to look like turquoise.  The other problem lies with turquoise itself- it's rather porous and can fracture easily, so it needs to be stabilized with epoxies and other plastics.   But many people accept the stabilization because otherwise, the stone would not be as useful in jewelry. Sometimes turquoise is even dyed, or its matrix (the dark parts) is, not acceptable to many jewelry artists.  Some turquoise is even reconstituted from little bits, a practice most would agree is too drastic.  Full disclosure of what treatments the stone has had is the best, so dealing with reputable purveyors of turquoise is your best bet if you want to buy the stone.

So how does turquoise get its dramatic colors? It's mostly from copper compounds (the blue) or some iron compounds (the green).  Dark brown or black limonite forms the characteristic veining one sees in turquoise.

Turquoise is mined in various places in the world, mostly dry areas, the American SW, China, the Middle East, and was one of the first minerals to be mined and used in jewelry, so it has had a long, rich history.

Check out my latest treasury:

Turquoise Treasures:

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