Eudialyte

Formula:   Na₁₆Ca₆Fe₃Zr₃(Si₃O₉)₂(Si₉O₂₇)₂(OH, Cl)₄

Origin of name:   From Greek eu = well and dialytos = dissolve

Crystal system:   Hexagonal

Crystal class:   3m

Twinning:

Unit cell: a = 14.31 Ǻ, c = 30.15 Ǻ

Colour:  Yellowish brown, brownish red, pink, red

Diaphaneity:

Luster:   Vitreous to greasy or dull

Habit:   Crystals thick to thin tabular, short to long prismatic or rhombohedral

Hardness:   5 to 5.5

Specific gravity:   2.74 to 2.98

Cleavage:   1; {0001} indistinct

Tenacity:   Uneven; brittle

Streak:   Colourless

Synonyms/varieties:   Barsanovite, eucolite

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