This specimen is mostly
calcite
with a beige colored, 3-4 mm arsenite rich layer containing abundant crystals
of
finnemanite and scattered zones of trigonite mineralization. Trigonite
occurs as both crystals and amorphous coatings on the unnamed mineral.
Finnemanite occurs as dark grayish brown crystals to 1.1 cm in length. The
unnamed arsenite analog of
friedelite and
schallerite was described by Peacor et al in 1986.
Origin: Långban, Sweden
Harry von Eckermann collection
Sample size: 9 x 7 x 4.1 cm
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