Among a series of specimens collected by Mr. H. G. Dines from the South Crofty mine, Illogan, one was found to contain bertrandite and beryl. The specimen was obtained from the back of the 290-fathom level, east of Robinson's shaft, in the no. 1 lode, which hades north and at this position is 3 feet 10 inches wide. The location of the specimen was about 9 inches from the granite footwall. In hand-specimen the rock is a normal stanniferous veinstone composed of massive quartz tinted grey-green by disseminated chlorite and tourmaline and traversed by stripes of blackish ‘peach’ and white vein quartz which run parallel to the lode walls. Microscopically it is composed essentially of quartz, chlorite, and tourmaline, with subordinate orthoclase, fluorspar, and cassiterite, accessory apatite, and local bertrandite and beryl. In its texture there is evidence of an early formation of stanniferous chlorite-tourmaline peach with quartz-fluorspar gangue, which was subsequently fractured and, later, more or less completely healed by an accession of quartz, some redistribution of the earlier minerals having taken place at the same time. The place of bertrandite and beryl in this general scheme is discussed below (p. 576).