A sharp miniature specimen of Cassiterite pseudomorph after Orthoclase, from the classic Cornish location of Wheal Coates. The Cassiterite forms an unusual 'V' twin of two Carlsbad law twinned crystals. The 'V' form habit is very rare even amongst these rare Cassiterite pseudomorphs. The twinned crystals show a typical matt brown granular texture. Most of these pseudomorphs came from a small stretch of a vein in the late 1820s. A real Cornish classic from Wheal Coates.