Hulsite

hulsite

szaibelyite

vesuvianite

magnetite

Images

Formula: Fe²⁺₂Fe³⁺O₂(BO₃)
Anhydrous borate
Specific gravity: 4.28
Hardness: 3
Streak: Black
Colour: Black
Solubility: Readily soluble in hydrochloric and hydrofluoric acids but less reactive in other acids
Environments

Metamorphic environments

Hulsite occurs very rarely in a contact metamorphosed limestone, close by a granite intrusion, associated with calcite, vesuvianite, magnetite, garnet, fluorite and diopside (HOM).

Localities

At the type locality, Brooks Mountain, Seward Peninsula, Nome Census Area, Alaska, USA, hulsite occurs in contact metamorphosed limestone associated with vesuvianite, magnetite, garnet and diopside (Mindat).

Hulsite alters to limonite (Mindat).

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