A particularly well formed double terminated specimen of the Cornish classic Cassiterite after Orthoclase Carlsbad twinned crystal, from the Wheal Coates, St. Agnes. The specimen displays the characteristic lustre of the granular light brown Cassiterite replacement of the Feldspar. Most of these pseudomorphs came from a small stretch of a vein in the late 1820s. A real Cornish classic from Wheal Coates