As black tourmaline or “schorl” is one of the most abundant and widely distributed of the minerals of the West of England, it is perhaps somewhat remarkable that the variously colored and colorless varieties are extremely rare both in Cornwa]l and Devon. Among recorded localities, I am not aware that the green or brownish green Zeuxite has occurred, except at Huel Unity, Carn Marth, and Great Work Mine, in Cornwall, and near Okehampton in Devon, while the colorless variety Achroite has only been observed at Roscommon Cliffs, in St. Just; and the red, blue, and yellow varieties are so far quite unknown in the two western counties. I have lately been examining a number of specimens obtained in a large open tin working at Rock Hill, in the parish of St. Austell, Cornwall, in 1871 and 1872, and among them I have found several specimens of Achroite. When I first obtained them I thought they were quartz, and, indeed, I referred to them as such in a paper which I read to the Miners’ Association of Cornwall and Devon, in 1872, but I am now satisfied that they are colorless tourmaline or kchroite.