Grumantite

grumantite

ussingite

makatite

kazakovite

Images

Formula: NaSi₂O₄(OH).H₂O
Phyllosilicate (sheet silicate)
Crystal System: Orthorhombic
Specific gravity:
Hardness: 4 to 5
Streak: White
Colour: White
Luminescence: Weak, bluish white fluorecence under UV
Solubility: Insoluble in cold water and cold 10% hydrochloric acid, readily soluble in hot 10% hydrochloric acid giving a silicic residue (Mindat)
Environments

Pegmatites

Localities

At the type locality, the Umbozero North quarry, Alluaiv Mountain, Lovozersky District, Murmansk Oblast, Russia, grumantite occurs in veins cutting alkalic feldspathoid-bearing pegmatites in a differentiated alkalic massif. Associated minerals include ussingite, makatite, kazakovite, tisinalite, nordite, sodalite, nepheline, potassic feldspar, arfvedsonite, aegirine, eudialyte and loparite (HOM).
Grumantite from the Alluaiv Mountain - Image

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