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Formula: Na10Ca9Zr3Fe2SiNb(Si3O9)2(Si9O27)2(OH)3(CO3).H2O
Cyclosilicate (ring silicate), eudialyte group,
zirconium- and niobium- bearing
mineral
Crystal system: Trigonal
Specific gravity: 2.89 measured, 2.889 calculated
Hardness: 5½
Colour: Brown to red-brown
Common impurities: K,Cl,Mn,(Al,Ce,La)
Environments
Although golyshevite was approved in 2004, to date (July 2025) it has been reported only from the type
locality.
Localities
At the type locality, the Kovdor Phlogopite mine, Kovdor Massif, Kovdorsky District, Murmansk Oblast, Russia,
golyshevite occurs in the northern face of the mica quarry in
pegmatite no. 10, a calcium-rich peralkaline
pegmatite. Associated minerals include
orthoclase, pectolite,
calcite, pseudomorphs of
thompsonite-Ca after
cancrinite, hedenbergite,
tacharanite and
aegirine-augite. It is dark
reddish brown in hand samples, with a white streak and glassy lustre, and can make up to 70% of the host rock.
Crystals are up to 2 cm long
(AM 92.8.1539-1540, HOM).
Golyshevite from the Kovdor Phlogopite Mine -
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