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. See a map of Anasazi and contemporary cultural areas. Text and graphics copyright 1995, 1996. Turquoise chunky necklace, heishii and mosaic on shell, silver squash blossom, and trading post pawn vault photos by Camille den Dooven, from Southwestern Indian Arts and Crafts, Tom Bahti, KC Publications 1966, 1977.