Axinite-(Fe) is best identified by its distinctive sharp, wedge-shaped crystals that often look like axe blades. It is a calcium-iron borosilicate typically found in contact metamorphic zones where hydrothermal fluids have altered calcareous rocks.
Is this axinite-(fe)?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch axinite-(fe) with a known reference. Axinite-(Fe) sits at Mohs 6.5-7, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: brown, purplish blue, gray, greenish yellow.
- 5Look at form & habitCrystal system: triclinic. Typical habit: lamellar, massive.
Often confused with
Axinite-(Fe) vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside axinite-(fe)
Minerals reported to co-occur with axinite-(fe). Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₂Fe²⁺Al₂BSi₄O₁₅(OH)
- Mohs hardness
- 6.5-7
- Density
- 3.27-3.29 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Triclinic
- Crystal habit
- Lamellar, massive
- Cleavage
- Distinct on {100}; poor on {001}; poor on {110}
- Rarity
- Uncommon
- Uses
- Collector, Gemstone
- Host rock
- Contact metamorphic, hydrothermal, and alpine vein rocks
Where rockhounds find axinite-(fe)
Classic worldwide localities
- Boug d'Oisans, France (type locality)
Field-hunting tip
Where it forms: Contact metamorphic, hydrothermal, and alpine vein rocks. If you start seeing quartz, calcite, epidote in float, you are in the right ground. Typical habit: lamellar, massive. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify axinite-(fe)?+
Where is axinite-(fe) found?+
What rocks look like axinite-(fe)?+
What minerals are found with axinite-(fe)?+
What kind of rock does axinite-(fe) form in?+
What is axinite-(fe) used for?+
Find axinite-(fe) on the map
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