Turquoise is a hydrated phosphate of aluminum and copper. Its color varies between sky blue, greenish blue and apple green. This gem often has brown, gray and/or black inclusions of other minerals from the parent rock from which it is extracted, in some cases forming veins that look like spider webs.

It has a score of 6 on the Mohs scale of hardness, which means its resistance is similar to that of a window glass.

Its name comes from Old French "Turquoise" which means Turkish. Turquoise does not come from Turkey, however, because it entered Europe through that country following the Silk Route, it was given that name. It was probably extracted in Persia where they called it "Feroza" or victory.

Known and appreciated for thousands of years, it is said to be one of the first stones to be extracted by humanity. It is rare and expensive when it is of gemstone quality and has been used as a gem, amulet and ornament ever since.

It adorned rulers of Ancient Egypt, Aztecs and probably other pre-Columbian Mesoamerican civilizations, Persia, Mesopotamia, the Indus Valley in India and partly in Ancient China.

The Aztecs embedded turquoise in gold along with quartz, malachite, jet, jade, coral, and shells to create mosaic objects presumed to be ceremonial such as masks (sometimes using a human skull as a base), knives, and shields. The Indians of the Pueblo culture, the Navajos and Apaches venerated it as an amulet; the latter said that it gave their archers deadly aim.

In Persia it was used for millennia as an ornament, adorning from turbans and horse bridles to mosques and other important buildings. Eventually the Persian techniques spread to India where they were used in jewelry with high purity gold with diamonds and rubies or in constructions such as the Taj Mahal.

It is estimated that the ancient Egyptians used it before the first Dynasty of pharaohs. The best known pieces that incorporate the use of turquoise were recovered from the tomb of Tutankhamun; notably the pharaoh's death mask which is inlaid with this gem along with lapis lazuli, carnelian and tinted glass.

For the Tibetans, turquoise has multiple virtues and a positive influence on the mind. It is a symbol of bravery, generosity and indulgence. It would allow those who suffer from depression to drive away negative thoughts and protect them from bad intentions.

It is said to be an emotional balancer that aligns the chakras and promotes meditation. Soothing for the rational mind, it is conducive to communication and artistic expression as well as inducing feelings of friendship and loyalty.

On the physical plane it represents an energetic reinforcement for the body. It promotes good blood circulation in addition to combating conditions of the respiratory system and harmonizing the nervous system. Besides, it is said to regenerate tissues and relieve rheumatism, arthritis and headaches.

The highest quality turquoise is mined in the northeastern region of Iran, near the city of Nishapur. We also find registered deposits in various parts of the United States, China, Tibet, Australia, India, Afghanistan and in some European countries. Many deposits of this gem are small-scale in remote locations where they are worked by hand, mostly without machinery and only part of the year.

Some variants exist such as Kingman turquoise with its light blue color and yellow copper inclusions and purple turquoise, a rare variety with intense violet tones from the Mojave Desert in California.