Dims: 4.0 x 2.6 x 1.3" (10.2 x 6.6 x 3.3 cm)
Wt: 3.86 oz. (109.6 g)
Bertha Mine, Dugway District, Tooele County, Utah, U.S.A.
This hand specimen consists of a dull gray-brown host rock on which rest dozens of Chalcanthite tendrils. These "crystals" have an unusual form that reminds me of "ram's horn" selenite. Their prism lengths are long compared to their diameters often curved, but a few of them do show definite termination faces. Though it is rather difficult to determine damage to them, I do believe that they are in at least moderately good condition. These tendrils achieve lengths of nearly 0.5" (1 cm) and tend to be gathered in clusters of parallel crystals (see the close-up image). Most of them, however, do not exceed 0.2" (5 mm). All have a moderate royal blue coloration that is one of their primary characteristics, and the luster of their prism faces is almost silky. Individual crystals may be transparent and quite clear, but the clusters are generally translucent. I am not certain, but I believe that these crystals formed due to huge evaporation mining processes that are common in the more arid climates of western and southwestern U.S.