Orthoclase : CSIRO Spectroscopy Database

Orthoclase [ KAlSi₃O₈ ]

Images of Orthoclase

CL spectrum of orthoclase from Bodenmais, Germany. Fig23 in Götze 2000c

Orthoclase specimen (27x17cm), from Minas Gerais, Southeast Region, Brazil

Photo by Didier Descouens (via Wikimedia Commons), CC-BY-SA 4.0

Material properties

Formula	KAlSi₃O₈
Abbreviation	Or
Classification	K feldspar
Luminescence emitters	AlO4, Al-O- -Al, Exsolution features, Fe, Mn, Pb, Si-O, Triplet-singlet
Spectra	Luminescence (1)
IMA Status	Approved (IMA 1962 s.p.)
Search other databases	webmineral.com, mindat.org, rruf.info, fluomin.org, mineralienatlas.de, Handbook of Mineralogy, American Mineralogist Crystal Structure Database
Related materials	Microcline
Tags	Mineral, Aluminosilicate

Composition

Element	Atoms
K	1
O	8
Al	1
Si	3
Total:	13

References for Orthoclase

Götze 2000c

1

Laukamp et al. 2021

0

0

Rendell & Clarke 1997

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0

Tarashchan 1978

0

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Specimens of Orthoclase

Name	Owner	Materials	Phase purity	Image	Spectra	Techniques
M1284 Orthoclase	CSIRO	Albite, Ca, Microcline, Muscovite-2M1, Orthoclase (86.9%), Quartz	86.9	M1284 Orthoclase Image of specimen 'M1284 Orthoclase' [CSIRO]. (C) 2026 CSIRO Mineral Resources. All rights reserved.	0	—
M2253 Covellite	CSIRO	Chalcanthite, Chalcopyrite, Covellite, Muscovite-1M, Muscovite-2M1, Orthoclase (16.0%), Quartz	16.0	M2253 Covellite Image of specimen 'M2253 Covellite' [CSIRO]. (C) 2026 CSIRO Mineral Resources. All rights reserved.	0	—
API13 Halloysite	CSIRO	Albite, Halloysite, Halloysite, hkl, Illite-Smectite 12.0A, Kaolinite, Montmorillonite, Orthoclase (7.9%), Quartz	7.9	API13 Halloysite Image of Kaolinite, Albite, Halloysite (var. hkl), Illite-Smectite 12.0A, Montmorillonite, Orthoclase and Quartz in specimen 'API13 Halloysite' [CSIRO]. (C) 2025 CSIRO Mineral Resources. All rights reserved.	0	—
M0762 Goethite	CSIRO	Goethite, Kaolinite, Muscovite-1M, Muscovite-2M1, Orthoclase (7.1%), Quartz	7.1	M0762 Goethite Image of Goethite, Kaolinite, Muscovite-1M, Muscovite-2M1, Orthoclase and Quartz in specimen 'M0762 Goethite' [CSIRO]. (C) 2026 CSIRO Mineral Resources. All rights reserved.	0	—
MES124 Hambergite	CSIRO	Albite, Ankerite, Cookeite, Hambergite, F, Microcline, Orthoclase (7.0%), Quartz	7.0	MES124 Hambergite Image of Microcline, Hambergite (var. F), Albite, Ankerite, Cookeite, Orthoclase and Quartz in specimen 'MES124 Hambergite' [CSIRO]. (C) 2026 CSIRO Mineral Resources. All rights reserved.	0	—
M1296 Petalite	CSIRO	Albite, Ca, Microcline, Muscovite-2M1, Orthoclase (5.8%), Petalite, Quartz	5.8	M1296 Petalite Image of specimen 'M1296 Petalite' [CSIRO]. (C) 2026 CSIRO Mineral Resources. All rights reserved.	1	Reflectance
NR62 Orthoclase	CSIRO	Albite, Microcline, Orthoclase (5.0%), Quartz	5.0	NR62 Orthoclase Image of Microcline, Albite, Orthoclase and Quartz in specimen 'NR62 Orthoclase' [CSIRO]. (C) 2026 CSIRO Mineral Resources. All rights reserved.	0	—
MT8367 Lithiophilite	CSIRO	Fluorapatite, Orthoclase (4.0%), Potassic-ferro-richterite, Quartz, Triploidite	4.0	MT8367 Lithiophilite Image of specimen 'MT8367 Lithiophilite' [CSIRO]. (C) 2026 CSIRO Mineral Resources. All rights reserved.	0	—
Swy-2 Montmorillonite	CSIRO	Montmorillonite, Orthoclase (3.5%), Quartz	3.5	Swy-2 Montmorillonite Image of Montmorillonite, Orthoclase and Quartz in specimen 'Swy-2 Montmorillonite' [CSIRO]. (C) 2026 CSIRO Mineral Resources. All rights reserved.	0	—
M2101 Pollucite	CSIRO	Orthoclase (3.0%), Pollucite, Quartz	3.0	M2101 Pollucite Image of Pollucite, Orthoclase and Quartz in specimen 'M2101 Pollucite' [CSIRO]. (C) 2026 CSIRO Mineral Resources. All rights reserved.	1	Reflectance
MES123 Pollucite	CSIRO	Orthoclase (3.0%), Pollucite, Quartz	3.0	MES123 Pollucite Image of Pollucite, Orthoclase and Quartz in specimen 'MES123 Pollucite' [CSIRO]. (C) 2026 CSIRO Mineral Resources. All rights reserved.	1	Reflectance
Swy-1 Montmorillonite	CSIRO	Montmorillonite, Orthoclase (2.8%), Quartz	2.8	Swy-1 Montmorillonite Image of Montmorillonite, Orthoclase and Quartz in specimen 'Swy-1 Montmorillonite' [CSIRO]. (C) 2026 CSIRO Mineral Resources. All rights reserved.	0	—
MES200 Quartz	CSIRO	Dolomite, Labradorite, Microcline, Orthoclase (2.0%), Quartz	2.0	MES200 Quartz Image of Quartz, Dolomite, Labradorite, Microcline and Orthoclase in specimen 'MES200 Quartz' [CSIRO]. (C) 2026 CSIRO Mineral Resources. All rights reserved.	0	—
MES201 Quartz	CSIRO	Albite, Ca, Aragonite, Calcite, Microcline, Orthoclase (2.0%), Quartz	2.0	MES201 Quartz Image of Quartz, Albite (var. Ca), Aragonite, Calcite, Microcline and Orthoclase in specimen 'MES201 Quartz' [CSIRO]. (C) 2026 CSIRO Mineral Resources. All rights reserved.	0	—
46E3372 Grossular	CSIRO	Albite, Albite, Ca, Fluorapatite, Grossular, Orthoclase (1.8%), Quartz, Titanite	1.8	46E3372 Grossular Image of Grossular, Albite (var. Ca), Albite, Fluorapatite, Orthoclase, Quartz and Titanite in specimen '46E3372 Grossular' [CSIRO]. (C) 2025 CSIRO Mineral Resources. All rights reserved.	0	—
MES119 Rhönite	CSIRO	Anorthoclase, Armalcolite, Augite, Hematite, Labradorite, Orthoclase (1.8%)	1.8	MES119 Rhönite Image of specimen 'MES119 Rhönite' [CSIRO]. (C) 2026 CSIRO Mineral Resources. All rights reserved.	0	—