These translucent, nailhead calcite crystals appear to have a dark mineral included in many of the terminations. This piece is from Charcas, San Luis Potosi, Mexico. The overall dimensions are 8.1 cm wide by 6.7 cm tall and 4.3 cm front to back. There is minor damage at the lower sides of the piece. The base of the piece has been cut so it will stand better.