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Formula: Ca3[B5O6(OH)6]FCl2.8H2O
Hydrated pentaborate
Crystal system: Monoclinic
Specific gravity: 1.933 calculated
Hardness: 3
Streak: White
Colour: Colourless
Luminescence: No fluorescence under UV
Environments
Popugaevite is a new mineral, approved in 2019 and to date (August 2025) reported only from the type locality.
Localities
At the type locality, the Internatsionalny Mine, Mirny, Mirninsky District, Sakha, Russia, popugaevaite
belongs to the low-temperature hydrothermal mineral assemblage formed in the contact zone between
kimberlite and a
boron-bearing halite rock.
Popugaevaite occurs as veinlets in massive aggregates of
ekaterinite and crusts (up to 0.7 mm thick and up to 1 cm × 4 cm in
area) on ekaterinite nodules embedded in
halite. Other associated minerals are
iron-rich szaibélyite,
serpentine, dolomite,
pyrrhotite and chalcopyrite.
Crude prismatic crystals of popugaevaite are up to 0.3 × 1 mm in size. The mineral is transparent and
colourless, with a vitreous lustre and one perfect cleavage
(MM 89.2.225–233).
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