Alunite specimens for sale
1 for sale · $600 USD
1 in the gallery
Alunite is a hydrous aluminum potassium sulfate mineral that forms in hydrothermal veins and alterated systems, typically presenting as tabular, rhombohedral, or prismatic crystals with a vitreous to pearly luster. Its color ranges from colorless to white, pink, or dull red, often exhibiting a vitreous to resinous surface on well-formed crystals and a characteristic tabular habit that reflects its layered sulfate structure.
- Formula
- KAl3(SO4)2(OH)6
- Rarity
- Common
- Stability
- Stable
- Collector interest
- Moderate Interest
- Classification notes
- Sulfates; alunite group (KAl3(SO4)2(OH)6)
Key characteristics
- Crystal system
- trigonal
- Mohs hardness
- 3.5–4
- Specific gravity
- 2.58–2.75
- Luster
- vitreous, pearly, dull
- Transparency
- transparent, translucent, opaque
- Color
- white, gray, yellow, brown, red
- Streak
- white
- Cleavage
- good
- Fracture
- conchoidal, uneven
- Crystal habit
- rhombohedral, tabular, granular, massive, fibrous
- Classic / historic
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About Alunite
Notable specimens come from hydrothermal zones and veins in Chile and Taiwan, where arid to semi-arid environments and altered volcanic rocks provide the fluids and chemistry that promote alunite growth. Collectors prize well-formed crystals with sharp faces, zoning, and distinct color, as well as matrix specimens that reveal association with other sulfates and aluminum minerals. Alunite’s occurrence in large, gymnastic crystals and its reflectivity under light make it attractive for cabinet displays and study alike, while its presence in classic alteration deposits gives it geological significance for provenance and paragenesis.