Penobsquisite

penobsquisite

boracite

hilgardite

pringleite

Images

Formula: Ca2Fe2+[B9O13(OH)6]Cl.4H2O
Hydrated borate with nine crystallographically distinct borate polyhedra, four of which are triangular BO3 groups and five of which are tetahedral BO4 groups (CM 34.3.657-665)
Crystal System: Monoclinic
Specific gravity: 2.26 measured, 2.27 calculated
Hardness: 3
Streak: White
Colour: Pale yellow
Luminescence: No fluorescence observed under lomg wave or short wave UV
Environments

Evaporite deposits

Localities

At the type locality, the Potash Corporation of Saskatchewan Mine, Penobsquis, Cardwell Parish, Kings County, New Brunswick, Canada, borate minerals from two potash mines in the Penobsquis-Sussex area of New Brunswick were first noted in the early 1980s in residue from the drilling operations. The list of borate minerals includes boracite, veatchite, colemanite, danburite, hilgardite-1A, hilgardite-4M, howlite, hydroboracite, priceite, szaibélyite, ulexite, volkovskite, pringleite, ruitenbergite, trembathite, strontioginorite, congolite, tyretskite, ginorite, inyoite and penobsquisite. Other minerals found with the borate assemblage include anhydrite, sellaite, fluorite, nickeline, pyrite, chalcopyrite, sphalerite, halite, sylvite, microcline, diopside, quartz, a mica group mineral, a clay mineral, hematite, limonite, magnesite, calcite, dolomite, monohydrocalcite and malachite. Organic material is present in several sections of core.
Penobsquisite was found in only one piece of drill core from the lower third of the Upper Halite member of the Potash Corporation of Saskatchewan mine, and is intimately associated with halite, boracite, hilgardite, pringleite, trembathite, sellaite, fluorite, hematite and malachite. Approximately 100 crystals in the size range 0.5 to 1.5 mm were separated (CM 34.3.657-665).

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