Turquoise is a very American gem, and that's how we keep it. Our turquoise is only from American mines, with only the minimum of treatment to make it sturdy enough to wear. If it is listed as natural, then there is no treatment. Only a very little turquoise is sturdy enough to not need treatment. Realize that over time it will absorb oils from the skin, and may acquire more green to its color. Otherwise our turqoise is stabilized, and resin impregnates the turquoise to make it sturdy enough for wear. Stablilized turquoise will not absorb oils or change color. No dye is added to our turquoise. There is no artificial coloring added, and it is not a composite. We will list any treatment given.