Diagnostic Features
Hardness: 6
Streak: White to pink
Luster: Nonmetallic
Specific Gravity: 2.6
Cleavage: Present (2 directions)
Fracture: None
Identification Tips
1. The mainly dark orange to salmon color of orthoclase is characteristic. It is a principal constituent of granites, gneisses and pegmatites.
2. Orthoclase commonly occurs with quartz and mica and is easily distinguishable by its color and cleavage.
Orthoclase
[Potassium Feldspar]
Photographs by Michael Amadeus Klimetz
Microcline
Catamarca Province
ARGENTINA
Microcline
Middletown
CONNECTICUT
Microcline
Estes Pegmatite
West Baldwin
Cumberland County
MAINE
Adularia
Canton Graubunden
SWITZERLAND
Adularia
Canton Graubunden
SWITZERLAND
Adularia
Canton Graubunden
SWITZERLAND
Adularia
Canton Graubunden
SWITZERLAND
Microcline
Pikes Peak
El Paso County
COLORADO
Microcline
Pikes Peak
El Paso County
COLORADO
Microcline
Parker Mountain Mine
Center Strafford
Strafford County
NEW HAMPSHIRE
Microcline
Parker Mountain Mine
Center Strafford
Strafford County
NEW HAMPSHIRE
Microcline
[Crystal Plate Illustrating Characteristic Orthogonal Cleavage Surfaces andTopped with Spessartine Garnet]
Shigar Valley
Northern Territories
PAKISTAN
Microcline
[Crystal Plate Illustrating Characteristic Orthogonal Cleavage Surfaces and Topped with Spessartine Garnet]
Shigar Valley
Northern Territories
PAKISTAN
Microcline
[Crystal Plate Illustrating Characteristic Orthogonal Cleavage Surfaces andTopped with Spessartine Garnet]
Shigar Valley
Northern Territories
PAKISTAN
Adularia
Blocky Transparent Crystals with Clinochlore on Matrix
Mirošov
Žďár nad Sázavou District
Vysočina Region
CZECH REPUBLIC
Amazonite
Terminated Crystal Tip
Teller County
COLORADO
Amazonite
Terminated Crystal Tip
Teller County
COLORADO
Amazonite
Terminated Crystal Tip
Teller County
COLORADO
Microcline
Cleaved Partial Crystal
Minas Gerais
BRAZIL
Microcline
Cleaved Crystals with Biotite and Quartz
West Side Excavation
Manhattan County
NEW YORK
Microcline
Terminated Compound Crystal
Crystal Peak
Teller County
COLORADO
Microcline
Terminated Compound Crystal
Crystal Peak
Teller County
COLORADO
