Alunite is a rock-forming sulfate mineral found in pockets or seams in volcanic rocks such as rhyolite or andesite.  This material was collected in the Quartzsite area years ago.  It is particularly desirable as a lapidary material because of the intense red streaks that developed in the presence of iron compounds during formation at the volcanic fumarole.  This collecting area has been completely dug out and the material is only available from old collections.

Origin:  Arizona

Dimensions:  5.5" x 3" and approximately 7.2 mm thick.  Weight = 197 grams. 

Shown wet.  Not polished. No known flaws.