Axinite
Axinite group
Uncommon · Ca₄(Fe,Mg,Mn)₂Al₄[B₂Si₈O₃₀](OH)₂
A complex calcium iron manganese boron silicate forming wedge-shaped crystals in skarns and metamorphic contact zones. Displays strong pleochroism, appearing brown, violet, or yellow depending on viewing direction.
Identity
- Formula
- Ca₄(Fe,Mg,Mn)₂Al₄[B₂Si₈O₃₀](OH)₂
- Chemical class
- Silicate
- Members
- Axinite-(Fe), Axinite-(Mg), Axinite-(Mn)
- Also known as
- Axinite-(Fe) (iron-rich, formerly ferroaxinite), Tinzenite (manganese-rich, calcium-poor member)
Crystallography
- Crystal system
- Triclinic
- Habits
- Tabular, Wedge-shaped, Massive
- Fracture
- uneven to conchoidal
Physical properties
- Mohs hardness
- 7
- Density
- 3.31 g/cm³
- Luster
- Vitreous
- Colors
- brown, violet-brown, gray, yellow, green
- Streak
- white
- Transparency
- Transparent, Translucent
Geology
- Origins
- Metamorphic, Hydrothermal
- Host rocks
- Granite, Marble, Limestone and chalk
- Associated minerals
- Prehnite, Garnet, hedenbergite, Calcite
- Found in
- Skarn
- Geography
- France, Russia, Mexico, USA, Pakistan
Classification
- Rarity
- Uncommon
- Gem quality
- Yes
Arcane properties
- Affinity
- Earth, Arcane
- Effects
- Warding, Elemental earth
- Planar origin
- Material Plane
Sources
- Axinite. Mindat.org (Hudson Institute of Mineralogy).
- 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, Ferroaxinite. Mineral Data Publishing, Handbook of Mineralogy, 2001.
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