Anorthite 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	Anorthite [ CaAl₂Si₂O₈ ] Anorthite specimen from the type locality at Somma-Vesuvius Complex, Naples Province, Campania, Italy. Size: 6.9 x 4.1 x 3.8 cm © 2010 Rob Lavinsky, iRocks.com, CC-BY-SA-3.0
Specimen temperature	Ambient
Technique	Cathodoluminescence (CL), using an optical microscope
Lines	Mn²⁺ 323 nm, 295.4 nm, 339 nm, 352 nm, 403 nm, 417 nm, 476 nm

Nominal composition of Anorthite [ CaAl₂Si₂O₈ ].
Element	Atoms	At%	Wt%
Ca	1	7.69	14.4
Al	2	15.4	19.4
Si	2	15.4	20.2
O	8	61.5	46