Find out more about it, see many pictures, here. T urquoise is a hydrous aluminum sulphate, colored by copper salts. Its primary use is personal, but it is also offered to the spirits, and crushed for use in ceremonial and healing sandpaintings. D issolved in water, the chemical compound is deposited into veins in porous rock called matrix or mother. This mother rock is responsible for the dark lines and blotches, which may include iron pyrites or bits of quartz.
Colors run from pale blue to dark green.
Quality of the stone depends on color, hardness and matrix. The most highly prized is a deep blue with dark spider web. Softer stones change color after long contact with body oils and soap to a dark green. C errillos, the largest of the early mines, extends 200 feet underground, and is 300 feet wide. Mining was done with stone hammers and antler picks, with fire used to crack the rock that holds the gem.