Hardness of turquoise used for jewelry usually varies from 5-6 on the Mohs scale. The hardest turquoise is usually found nearest the surface of the earth, where it's had a chance to dry, or cure. Softer turquoise is chalk-like -- too soft and porous to be used unless it's treated.

Handle your turquoise jewelry carefully to avoid scratching it. Don't store turquoise with harder gemstones or other materials that might rub against it and cause damage.

Keep turquoise away from high heat and chemicals such as oils, perfumes, and household cleaners. Care should therefore be taken when wearing such jewels: cosmetics, including sunscreen and hair spray, should be applied before putting on turquoise jewelry, and they should not be worn to a beach or other sun-bathed environment. Prolonged exposure to direct sunlight may also discolor or dehydrate turquoise . Even stabilized turquoise can be affected by a constant bombardment of chemicals.

Clean your turquoise in warm, sudsy water and dry it immediately with a soft cloth. Avoid commercial jewelry cleansers.

Why is Turquoise Different Colors?                                                                     

The blue in turquoise is enhanced when copper is present. If the area where turquoise is formed contains more aluminum, the turquoise will shade to green. When zinc is present, the deposits are a yellow-green color, a rare combination that so far has been found in only a few areas, including the Carico Lake and Blue Ridge mines in Nevada.

Why Are There Dark Markings in Turquoise?                                                     

That's the matrix, the rock that the turquoise formed in. When stones are cut, some of the matrix remains bound to the turquoise. Matrix color varies because turquoise can form in different types of rock.

·         Black matrix may be iron pyrite

·         Yellow matrix could be rhyolite

·         Brown is probably iron oxide

·         The term spider webbing refers to stones with thin lines of matrix distributed   throughout them