Umbite

umbite

kostylevite

wadeite

eudialyte

Images

Formula: K₂ZrSi₃O₉.H₂O
Valence: K₂Zr⁴⁺Si₃O₉.H₂O
Inosilicate (chain silicate), single and multiple chains, umbite group, zirconium-bearing mineral, paramorph of kostylevite
Crystal System: Orthorhombic
Specific gravity: 2.79 measured, 2.79 calculated
Hardness: 4½
Colour: Colourless, light yellow
Luminescence: Weak yellowish fluorescence under UV, photoluminescence at room-temperature. Fluorescence is bright whitish-green at the temperature of liquid nitrogen.
Solubility: Readily decomposed by cold 10% hydrochloric acid, leaving a silica skeleton.
Common impurities: Ti,Hf,Fe,Na,F
Environments

Pegmatites

Localities

At the type locality, the Vuonnemiok River Valley, Murmansk Oblast, Russia, umbite occurs in a pegmatite in the differentiated alkalic massif. Associated minerals include kostylevite, wadeite, eudialyte, K-feldspar and aegirine (HOM).
Umbite from Murmansk Oblast - Image

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