Chalcedony, Cyrptocrystalline Quartz

Chalcedony, a cryptocrystalline form of quartz, is a frequent find while out on the landscape around the Painted Pony Resort.  Pieces of various sizes are often found in association with archeological sites or found siting isolated on the surface.  Chalcedony forms from low temperature silica rich solutions and exhibits a pleasing convoluted form which is easy to spot while walking.  Generally smooth in appearance with a waxy luster, in some cases the specimen will be covered in a layer of small quartz crystals which sparkle in the sunlight further highlighting the specimen on the ground.  Unlike large single or multiple crystals commonly associated with quartz the crystalline formation of Chalcedony results in smaller crystals and the overall appearance is a translucent light colored rock with convolutions.  Formed in veins, chalcedony is found in a variety of host rock (including basalts) filling cracks and crevices.  Although no veins of chalcedony have been located in either mountain range the presence of specimens in the valley suggest veins of chalcedony exist somewhere locally. 

Evidence of the use of chalcedony by prehistoric peoples in the area is shown in the second image below.  The base of a translucent chalcedony lanceolet projectile point found about 1 mile west of PPR in the Amigos del Cielo air park suggests that not only did earlier residents find chalcedony pleasing in shape and appearance but also a useful source material for tools.

cryptocrystalline quartz
a 2" x 4" Chalcedony specimen

chalcedony arrowhead base
Chalcedony arrowhead base


  1. Always interesting to see what people find walking around the Boot Heel!

  2. I always wondered about that stuff. Some pieces are very beautiful.

  3. Thanks, The waxy luster and convoluted patterns found in some specimens always attract my attention. Found another piece of chalcedony this afternoon while working down by the hanger (back flushing irrigation lines).