Anhydrous borate, ludwigite group
Specific gravity: 3.84
Streak: Yellowish brown
Colour: Reddish brown
At the type locality, Långban, Filipstad, Värmland County, Sweden, fredrikssonite occurs in dolomite in a metamorphosed iron-manganese orebody. It has been found here in two assemblages. In one sample it was associated with calcite, adelite, brucite and hausmannite; in another sample it was found with clinohumite, calcite and jacobsite (AM 71.227).
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