Topaz

A 1.5 x 0.9 x 0.5 cm perfectly terminated Topaz crystal protruding vertically from a small block of volcanic matrix encrusted with a creamy white earthy coating.  The root beer brown Topaz is transparent with glassy prism faces and has micro-stippled terminations.  This fine large thumbnail is from Mun. de Villa de Arriaga in San Luis Potosí, Mexico.  The name in the locality provided is “Tepetate” and is thought to be the Mexican term for a geological feature rather than a place name.  It describes a compacted or cemented geological horizon found in volcanic areas of Mexico.