Mineralpedia Details for Ilmajokite

Named for the type and only locality near the Il’majok River in the Kola Peninsula in Russia. Ilmajokite is a rare mineral that occurs only at its type locality “on the walls of cavities in the central natrolite zone of pegmatites in a differentiated alkalic massif.” Associated minerals include sphalerite, halite, mountainite, nahcolite, and aegirine. Ilmajokite is water soluble.

Ref. Handbook of Mineralogy, Anthony et al (1995) and MSA at http://www.handbookofmineralogy.org/pdfs/ilmajokite.pdf

Formula

(Na,Ce,Ba)₁₀Ti₅Si₁₄O₂₂(OH)₄₄·nH₂O 

Crystal System

Monoclinic 

Crystal Habit

Prismatic, Platy, Granular 

Cleavage

Perfect, Perfect, None 

Luster

Vitreous (Glassy) 

Color

bright yellow, light yellow 

Streak

white 

Class

Monoclinic 

Hardness

1 

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Ilmajokite, a rare titanium silicate, was the first new mineral discoverd from this pegmatite. The coverage is about 4x3mm.