Pecos Valley Diamonds


New Mexico, one of the nation’s most mineralized states, contains a very large quantity quartz (Si02) . ” This ubiquitous mineral occurs in every district and in many forms. The crystals known as “Pecos Valley ‘Diamonds” however, are found only in the Pecos River Valley, an area 20 miles wide and a north-south distance of about 100 miles; centering in Roswell, New Mexico.

During the Permian time of the Paleozoic era (300,000,000 years ago) the great Capitan Barrier Reef grew, trapping the Permian Sea, Evaporation of the sea left the gypsum beds of the Permian-Whitehorse formation. Time and erosion have released the quartz crystals embedded in the gypsum where they had originally crystallized. These crystals occur as doubly terminated hexagonal prisms. Although generally small, crystals up to several inches in length are known -some are semi-transparent, but the majority are translucent to opaque. They vary from colorless to white, pink, yellow, orange, red, green, brown, and black shades. Although quartz replacing gypsum is not uncommon, the development of such doubly terminated crystals by its replacement is unusual.

The “diamonds” were first observed and recorded in 1583 by Don Antonio de Espejo, one of the Spanish new world explorers. It is known that they were used as drills by the early cliff dwellers of the southwest region (they have a hardness of seven). Latter day Indians used them as ceremonial tools and for jewelry. In some areas along the Pecos River Valley, when the rays of the western sun are slanted, the innumerable brilliant sparkles give the impression that the desert is literally paved with diamonds; these then are the Diamonds of the Pecos Valley.

Original card from out-of-business rock shop: pecos-valley-diamonds

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