Cacoxenite
Species
Rare · Fe³⁺₂₄AlO₆(PO₄)₁₇(OH)₁₂·75H₂O
An iron phosphate in golden needle-like tufts and radiating spheres, a common accessory of oxidised iron ores. Its name means bad guest in Greek: the phosphorus it brings spoils the iron smelted from those ores.
Identity
- Formula
- Fe³⁺₂₄AlO₆(PO₄)₁₇(OH)₁₂·75H₂O
- Chemical class
- Phosphate
Crystallography
- Crystal system
- Hexagonal
- Habits
- Acicular, Fibrous, Botryoidal
- Fracture
- Uneven
Physical properties
- Mohs hardness
- 3
- Density
- 2.4 g/cm³
- Luster
- Silky
- Colors
- brownish yellow, green, yellow, golden yellow, red yellow
- Streak
- yellow
- Transparency
- Translucent
Geology
- Origins
- Sedimentary, Hydrothermal
- Host rocks
- Granite
- Associated minerals
- Wavellite, beraunite, rockbridgeite, strengite
- Found in
- Pegmatite deposit
- Geography
- Czech Republic, USA, Germany
Classification
- Rarity
- Rare
- Gem quality
- No
Sources
- M. Pasero and others, IMA Commission on New Minerals, Nomenclature and Classification, The New IMA List of Minerals, updated September 2026. International Mineralogical Association (CNMNC), 2026.
- J. W. Anthony, R. A. Bideaux, K. W. Bladh, M. C. Nichols, Cacoxenite. Mineral Data Publishing, Handbook of Mineralogy, 2001.
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