Phosphate of Lime, Apatite
- Div. 1. Crystallized.
The fine specimens of Tourmaline, tab. 548, from near Chudleigh, as I have observed, are accompanied by Phosphate of Lime, of which the crystals are far superior to any before met with in Great Britain: some, it is said, were found more than two inches long, whereas, formerly, half an inch was considered an extraordinary size. Mr. Brooke, who was so fortunate as to obtain several upon the spot, has kindly allowed me to engrave his finest; it forms the front figure in the plate. The upper figure is from a variety found last year at Caldbeck Fell, Cumberland, in a vein of Quartz ; it is accompanied by hexahedral laminæ of Mica, Mispickle, Pyrites, and that rare British mineral Sulphuret of Molybdenum, tab. 288, in well-defined hexahedral plates, and considerable abundance.
Phosphate of Lime has been found principally in Cornwall, in several parts of which inferior specimens occur, in general accompanied by Oxyde of Tin; I have one from Saint Michael’s Mount, gathered by Mr. E. Davy. Since my former figure was published, I have reason to suspect that the lower specimen exhibited upon plate 205 is foreign, though it was in Mr. Day’s collection as British, I have taken the liberty to represent one or two of the smaller crystals perfect, that were bruised by the ill usage alluded to in the description of the Tourmaline.