Turquoise has been one of the most popular and highly sought after gemstones for thousands of years. It forms from the alteration or weathering of existing rocks rich in aluminium mainly in arid environments. The main constituent in most commercial grade turquoise is a mineral called planerite.
Turquoise is a relatively soft and fragile mineral which needs to be handled carefully. Stones can fade or change colour completely because of long term exposure to bright sunlight, acidity and even moisture from the skin. After handling it's a good idea to wipe turquoise with a lint free cloth. Gemstones and other polished material is often impregnated with wax or resin which does offer some level of protection.
This gem grade turquoise cabochon could be used to create an exciting piece of jewellery. The front of the stone has a vitreous lustre whilst the back is dull. Dull means the surface absorbs light instead of reflecting it.