Several other primeval cultures have also treasured this azure gem and we see turquoise being used by the Aztecs, Native American Indians Tiffany Bracelets and many other ancient people like the Chinese, Mongolians and Persians. In fact, Persia was a prominent trader of turquoise from the early days onwards. The birthstone of December, turquoise is also prized for its mystical and healing properties. The stone's beneficial impact on the wearer has been a longstanding belief. Right from the olden times, it was believed that turquoise brought fame, prosperity, luck and health and hence the stone was also used to make charms, amulets and fetishes Tiffany Earrings, apart from jewellery. The appealing colour of turquoise is determined by several factors and also has a definite effect on its value. The true blue turquoise is valued much higher than then a greenish shade or even a speckled one. Clear blue Persian turquoise is considered the most exquisite though most of the superior quality blue turquoise today is mined at the Sleeping Beauty Mine near Arizona. Mines in China yield a unique lime-green coloured turquoise Tiffany Rings while India produces greenish blue turquoise. In fact, turquoise has a broad range of colours ranging from dark teal blue as well as sky blue to greenish hues. This is due to the amount of mineral present - the blue shade is deepened when there is copper in the site, the green shade is present when there is aluminium, a yellowish-green tint is observed if there is presence of zinc. This yellow-green turquoise is, however, a rare variety, mined in the Orvil Jack mines in Nevada. This type of turquoise is fast gaining huge popularity in manufacturing Tiffany & co jewellery and accessories all over the world. The dark markings in the turquoise stone are the matrix or the impressions of the rock that the turquoise was formed in. Attractive matrix patterns enhance the beauty of the stone. Only Persian turquoise occurs without any apparent matrix. Turquoise is not a hard stone having a score of only 5-6 on the Mohs scale. It, therefore, has to be treated with resin, paraffin or wax to stabilize or harden it. In America, a new treatment called the Zachery treatment is also used to harden the stone without change of colour thereby increasing durability. Natural turquoises which can be used without chemical treatment are very high quality stones and are therefore exorbitant.