Orthoclase CL/OM measurement, Telfer & Walker 1978

Reference	Telfer D. J. & Walker G. (1978). Ligand field bands of Mn2+ and Fe3+ luminescence centres and their site occupancy in plagioclase feldspars. Modern Geology, 6(4), 199-210.
Material	Orthoclase [ KAlSi₃O₈ ] Orthoclase specimen (27x17cm), from Minas Gerais, Southeast Region, Brazil © Photo by Didier Descouens (via Wikimedia Commons), CC-BY-SA 4.0
Specimen temperature	Ambient
Analysis technique	Cathodoluminescence (CL), using an optical microscope
Lines	Fe³⁺ 14060 cm-1, 13230 cm-1, 13400 cm-1, 13450 cm-1, 12800 cm-1, 13600 cm-1, 14710 cm-1, 14770 cm-1, 14330 cm-1

Nominal composition of Orthoclase [ KAlSi₃O₈ ].
Element	Atoms	At%	Wt%
K	1	7.69	14
Al	1	7.69	9.69
Si	3	23.1	30.3
O	8	61.5	46