Delhayelite

delhayelite

kalsilite

gotzenite

kitschsteinite

Images

Formula: K₇Na₃Ca₅Al₂Si₁₄O₃₈F₄Cl₂ Phyllosilicate (sheet silicate)
Crystal System: Orthorhombic
Specific gravity: 2.60 measured, 2.50 calculated
Hardness: 4 to 5
Streak: White
Colour: Colourless, silver-grey, greenish grey
Environments:

Volcanic igneous environments

Delhayelite is easily hydrothermally altered to hydrodelhayelite (Mindat).

Localities

At the Type Locality, Mount Shaheru, Nyiragongo Volcano, Nyiragongo Territory, North Kivu, DR Congo, delhayelite occurs in a kalsilite-bearing melilite-nepheline lava. Associated minerals include kalsilite, nepheline, götzenite, combeite and kirschsteinite (HOM, MM 32.6-9).

At the Khibiny Massif, Murmansk Oblast, Russia, delhayelite is associated with fenaksite, eudialyte and lomonosovite (HOM).

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