Turquoise

gemstone · mineral · copper · blue-green

Rare and valuable. Turquoise is an opaque mineral that's quite rare, especially in high-quality grades. The finest turquoise has been cherished as a precious gemstone for thousands of years.

Made from copper. Turquoise is actually a hydrous phosphate of copper and aluminum, which means it's a combination of these metals plus water and phosphorus. That copper is what gives turquoise its beautiful blue and green colors.

Blue to green hues. Turquoise gets its name from its stunning color, which ranges from bright blue to soft green. The exact shade depends on how much copper and other minerals are mixed into the stone.

Chemical formula. Scientists write turquoise's chemical makeup as CuAl6(PO4)4(OH)8·4H2O, which shows it contains copper, aluminum, phosphate, hydroxide, and water molecules. This exact recipe is what makes turquoise so special.

Ancient treasure. People have valued turquoise for thousands of years and used it to make jewelry, ornaments, and decorative items. Many ancient civilizations considered it a precious and sacred stone.