Kentbrooksite

kentbrooksite

kupletskite

lavenite

hjortdahlite

Images

Formula: (Na,REE)₁₅(Ca,REE)₆Mn₃Zr₃Nb(Si₂₅O₇₃)(O,OH,H₂O)₃(F,Cl)₂
Cyclosilicate (ring silicate), eudialyte group, rare earth elements, manganese-, zirconium- and niobium- bearing mineral
Crystal System: Trigonal
Specific gravity: 3.10 measured, 3.08 calculated
Hardness: 5 to 6
Streak: White
Colour: Yellow-brown
Luminescence: Not fluorescent
Electrical: Strongly pyroelectric
Common impurities: REE,Y,K,Sr,Fe,Al,Ti,(Hf,Mg)
Environments

Pegmatites

Localities

At the Poudrette Quarry, Mont Saint-Hilaire, La Vallee-du-Richelieu RCM, MonteRegie, Quebec, Canada, kentbrooksite has been found with aegirine (Mindat photo).
Kentbrooksite from the Poudrette Quarry - Image

At the type locality, the Kentbrooksite occurrence, Amdrup Firth, Kangerlussuaq Fjord, Sermersooq, Greenland, kentbrooksite occurs in alkaline pegmatitic bodies cutting pulaskite. Associated minerals include kupletskite, låvenite, catapleiite, hiortdahlite, eudialyte, K-feldspar, nepheline, aegirine and albite (HOM).

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