Orthoclase from selected localities.
||Wilson, A. C. (1975). An Occurrence of Sapphire in the Land's End Granite, Cornwall. HM Stationery Office.|
||Reid, C., Flett, J.S., Wilkinson, B.S.N., Dixon, E.E.L., Pollard, W., and MacAlister, D.A. (1907): The Geology of the Land's End District. HMSO Publications (London), p. 47|