Fresnoite

fresnoite

bario-orthojoaquinite

taramellite

benitoite

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Formula: Ba₂TiO(Si₂O₇)
Sorosilicate (Si₂O₇ groups)
Crystal System: Tetragonal
Specific gravity: 4.43 measured
Hardness: 3 to 4
Streak: White
Colour: Lemon to canary yellow
Solubility: Insoluble or only slightly soluble in most cold dilute acids and bases; it is decomposed by hot 1:1 hydrochloric acid and cold glacial (anhydrous) acetic acid. It is partially melted when heated to 1200^oC, and completely melted at 1300^oC to a yellow glass (AM 50.335).
Common impurities: Al,Fe,Mn,Mg,Ca,Sr,K
Environments:

Metamorphic environments

Localities

At the Gun claim, Wilson Lake, Itsi Mountain, Watson Lake mining district, Yukon, Canada, fresnoite occurs with gillespite, sanbornite, taramellite, pellyite, muirite and baryte (HOM).

At the Esquire No. 1 claim, Rush Creek, Rush Creek deposit, Big Creek-Rush Creek Mining District, Fresno county, California, USA, fresnoite occurs with bario-orthojoaquinite, benitoite, baotite and natrolite (HOM).

At the type locality, the Esquire No. 7 claim, Big Creek, Rush Creek deposit, Big Creek-Rush Creek Mining District, Fresno county, California, USA, fresnoite occurs in sanbornite-bearing metamorphic rocks which outcrop in a narrow zone near a granodiorite contact, and in quartzite that is poor or lacking in sanbornite. Locally it is concentrated in thin layers in quartzite associated with celsian, taramellite, diopside and pyrrhotite. The individual grains are generally less than 1 mm long (AM 50.314-340).

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