New Mexico Mineral Symposium — Abstracts

Several good collecting sites have been found recently in the extrusive andesites near the Gila Cliff Dwellings National Monument. Specimens of the zeolite minerals chabazite, mesolite, stilbite, heulandite, analcime and levyne have been found. Associated minerals are quartz, commonly with pagoda or scepter terminations, calcite and rarely apopophyllite. All of the specimens found so far have been along more easily accessible locales along forks of the Gila River.

Up to the Middle Fork of the Gila River have been found chabazite crystals over an inch on an edge, heulandite crystals over one-half inch long and stilbite crystals over an inch long. Occasionally found associations may include one-third inch chabazite crystals on an amygdular section composed mostly of pagoda and quartz scepters; or a stilbite bowtie sitting on well-formed one-quarter inch heulandite cyrstals.

Near the junction of the East Fork of the Gila River with the Gila River are sporadic concentrations of mesolite. Mesolite amygdules are typically small, but have been seen to reach over five inches. The mesolite may occur as acicular puffballs or as a complete fuzzy lining. Associated zeolites with the mesolite are heulandite, chabazite, stilbite, analcime and in only three specimens, levyne.

Thus far, only a small portion of the total possible areas of zeolite occurrences in the Gila have been investigated by mineral collectors. As "new" areas are investigated certainly some good locales will come to light and, possibly, other zeolite species can be added to the current-list.