Mineralpedia Details for Axinite-(Fe)

Previously called Ferroaxinite, this mineral is named for the dominance of ferroan iron (Fe²⁺) in the chemical formula and as a member of the Axinite Group, which in turn received its name from the Greek word for “axe” in reference to the sharp crystal habit. Axinite-Fe is an uncommon mineral, with localities for fine crystals in England, France, Switzerland, Russia, Japan, the United States, Canada, Mexico, and Brazil. It occurs in various grades of regionally metamorphosed rock, contact metamorphic rock, and pegmatites.

Ref. Handbook of Mineralogy, Anthony et al (1995) and MSA at http://www.handbookofmineralogy.org/pdfs/ferroaxinite.pdf

Formula

Ca₄Fe²⁺₂Al₄[B₂Si₈O₃₀](OH)₂ 

Crystal System

Triclinic 

Crystal Habit

Massive - Granular, Lamellar 

Cleavage

Distinct, Poor, Poor 

Luster

Vitreous (Glassy) 

Color

brown, purplish blue, gray, greenish yellow 

Streak

white 

Class

Triclinic - Pinacoidal 

Fracture

Brittle - Conchoidal 

Hardness

6.5-7 

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Well-formed and very nice, lustrous Axinite crystals to 6mm

Cute little combo specimen with several purplish brown, bladed crystals of Axinite to 5mm associated with Arsenopyrite crystals.

It's hard to tell from the photos, but this specimen is one single crystal with faces on all sides. The color is a dark purplish brown and is translucent.