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Desert Diary


Agate, Amethyst, Citrine, Jasper, Rock Crystal, Rose Quartz—all things of beauty, of course, but what else do these minerals have in common? Why the fact that they all are variations of quartz! Add a little of this or a little of that to silicon dioxide, and colorful beauty appears. Of course, add a little bit of something else, and you're likely to get a rock as ugly as sin.

Natural characteristics of quartz have long been taken advantage of by pre-modern peoples. It's extremely hard and fractures much like thick glass, a so-called conchoidal fracture. As a result, non-flawed quartz makes ideal material for the manufacture of arrowheads. And all fans of history know that another form of silicon dioxide, flint, was struck with steel to produce a spark--a spark to start a fire or to fire a flintlock musket. For something almost magical, search among our desert gravels until you find a couple of smooth, egg-sized pieces of quartz. Grind them together in a very dark place—and watch a mystical glow appear at the contact!
pen and ink


Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.

Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.



Web Resources

Quartz Mineral Data

USGS "Magic" Quartz Pebbles