This matrix specimen features extremely lustrous, columnar, metallic gray, crystals of arsenopyrite to 3.0 cm in length, along with arsenopyrite-coated, quartz crystals, to 1.75 cm in length. This area, east of Penzance, is far less known than many of its neighbors. I got this piece out of a generally good source, but it has no older verifying labels. Just to be on the safe side, I did show it to a Cornwall dealer at Denver for confirmation with the result that it seemed "likely" to be legitimate as advertised. It certainly is distinct from other old arsenos from Portugal or Mexico!