Guide
Orthoclase specimens for sale
32 for sale · $50–$8,500 USD
267 in the gallery
Orthoclase is a potassium feldspar that crystallizes in the monoclinic system. It typically forms clear to pearly, colorless to light pink or yellow crystals with a vitreous to pearly luster and a characteristic triclinic cleavage. Specimens often occur as well-formed prismatic crystals or aggregates in pegmatites and granitic rocks, sometimes displaying a warm pink or creamy hue that is attractive to collectors.
- Formula
- K(AlSi3O8)
- Rarity
- Common
- Stability
- Stable
- Collector interest
- Moderate Interest
- Classification notes
- Silicate minerals; tectosilicates; feldspars (K-feldspar)
Key characteristics
- Crystal system
- monoclinic
- Mohs hardness
- 6–6.5
- Specific gravity
- 2.55–2.63
- Luster
- vitreous, pearly
- Transparency
- transparent, translucent, opaque
- Color
- colorless, white, gray, yellow, pink, red
- Streak
- white
- Cleavage
- perfect
- Fracture
- uneven, conchoidal
- Crystal habit
- prismatic, tabular, granular, massive
- Gem mineral
- Classic / historic
Buy Orthoclase specimens
View all 32Where Orthoclase is found
Top localities
- Wheal Coates14 specimens
- Pakistan10 specimens
- Erongo Mountains9 specimens
- Baveno9 specimens
- Mount Malosa7 specimens
- Wushan Spessartine Mine7 specimens
- Pitwak Mine5 specimens
- Organ Mountains5 specimens
- Capelinha4 specimens
- Valenciana Mine4 specimens
Guides
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About Orthoclase
Notable specimens come from classic localities in Pakistan, Namibia, the United Kingdom, the United States, and Italy, where orthoclase occurs alongside other feldspars and minerals in coarsely crystallized rock matrices. Collectors prize sharp terminations, clean faces, and the overall clarity of well-preserved crystals, especially when twinned or associated with quartz or microcline. The mineral’s straightforward identification, broad occurrence, and variety of habits make orthoclase a staple in many lore-filled mineral cabinets and display cases.
