Dims: 1.2 x 1.0 x 1.0" (3.0 x 2.5 x 2.5 cm)
Wt: 2.5 g
Centralia, Columbia County, Pennsylvania, U.S.A.
This odd little specimen consists of a portion of a "crust" of Sal Ammoniac that was created through fumarolic activity caused by a fire in a coal mine. As the hot exhaust gases escaped, they coated the nearby ground with layers of the ammonium chloride mineral. This particular piece shows absolutely no evidence of crystal form, and has a dull yellow coloration and a matte luster. It is also essentially opaque and has a low mass, due to an almost spongelike internal structure. A few small pieces of what might be a rusty shale base rock are attached.