Dims: 6.1" x 3.9" x 2.4"(15.5 x 9.9 x 6.1 cm)
Wt: 2lbs., 0.9 oz.(932 g.)
Czar Drift, Mine #29, Washington County, Missouri, U.S.A.
A thick chunk of calcitic limestone that is covered with a crust of hundreds of Marcasite crystals makes up this specimen. The Marcasites do not exceed 0.5" (1.3 cm) in any dimension, and occur in both an rectangular tabular form and a prismatic form with a diamond-shaped cross-section. They have the standard metallic luster of the mineral, but have a rather unusual orange-brown, coppery coloration. Along one edge of the crust, one can see the some of the crystals' cross-sections, and the familiar green-yellow coloration. A single calcite scalenohedron juts out of the crust, towering over the Marcasites; it has excellent form, and only a tiny chip cleaved off of its tip. Its color is a pale yellow and it has a pearly luster and dim transparence that is interrupted by internal fractures and cleavage lines. It is a large specimen from a locality that is unknown to me.