Sphalerite (twinned)
Concepcion del Oro, Zacatecas, Mexico
Thumbnail, 2.3 x 1.1 x 0.8 cm

Uncommon twin of gray-black Sphalerite from Concepcion del Oro in Zacatecas, Mexico. The Sphalerite crystals have a silky, bright luster and sharp form. The back is perfectly cleaved, but the twinning plane is quite evident from the presentation side. Overall, a good, and unusual, thumbnail for a classic Mexico locale.