Turquoise: What to Know Before You Buy

The Best, the Not-So-Good and the Fake; Can You Spot Them?

Think you know turquoise when you see it? It seems straightforward: the blue gemstone is familiar to most of us. Unfortunately, this is a frequently faked gem. Dig deeper and you'll learn that place of origin, mineralogical factors and man-made alterations all come into play when determining value and quality. Know before you buy.

Why are there different types of turquoise? Simply said, because it can be made up of different materials. Turquoise isn't a primary mineral. This means it develops as a result of geological forces on other existing minerals. It always forms in desert regions and always in the presence of copper. The weathering action of groundwater together with copper, phosphate and aluminum over time forms the gemstone.

Sometimes brown or black veins or traces of the mother stone run through turquoise. This is called matrix and it can look like a spider web. Chunks of pyrite or fool's gold might be included, too. If there is no visible matrix and the turquoise is pure, intense robin's egg blue, it's considered the finest turquoise. For thousands of years, Persia, or Iran as it's known today, was the source of the most valuable turquoise. It is Iran's national stone.

In other locales, iron substitutes for the aluminum to varying extents and turquoise takes on a greener color. Depending upon the place of origin and the mineral composition, turquoise can be powder blue, green, whitish, or yellowish blue.

In Israel, a beautiful mixture of turquoise with malachite and chrysocolla called Solomon's Stone, or Eilat stone is popular. This is Israel's national stone.

Turquoise is abundant in the American Southwest desert. Native Americans used it for centuries and as copper mining grew, more turquoise deposits were found with the copper. Often the turquoise was simply dumped as a waste product of the mining process. Arizona, Colorado, California, New Mexico and Nevada all have deposits.