Hardness 5-6, Specific gravity 2.6-2.8, Refractive index 1.61-1.65

Turquoise is usually blue green to apple green; sky blue stones are not as common as most people think.

Turquoise is used as a birthstone. It maintains its color in artificial light. The color of turquoise fades over time. It should not be placed in water and should be handled carefully-it is a soft stone that is easy to scratch or break. Turquoise can become discolored by absorbing oils or pigments.Turquoise is found in Mexico, Australia, Egypt, Russia, Tibet, China, Afghanistan, and the USA. The main source is the USA's northwestern states. Sometimes turquoise is painted with a blue dye, then coated in clear plastic. Pale and chalky turquoise is often treated with oil, clear plastic, or glycerin.If the stone fades just after it is first put on, it should not be used. It is believed that turquoise will change color to warn the wearer of coming disaster.

One who wears turquoise will find happiness, joy, and honesty. Turquoise can be worn by aristocratic and spiritually-minded people to good benefit. It is said to protect one from curses, violence, accidental death, and enemies. If it is placed against the eyes, it can help eye problems. It can also help with headaches, physical pain, liver problems, and throat infections.