Steenstrupine-(Ce)

Formula: Na₁₄Ce₆Mn₂Fe₂Zr(PO₄)₇Si₁₂O₃₆(OH)₂.3H₂O

Origin of name: for Knud Steenstrup, Danish geologist

Crystal system: hexagonal

Crystal class: -3 2/m

Twinning:

Unit cell: a = 10.46 Å, c = 45.48 Å

Colour: brownish red to black

Diaphaneity: opaque

Luster: dull

Habit: crystals rhombohedral, irregular masses, to 10 cm

Hardness: 5

Specific gravity: 3.1 to 3.6

Cleavage: none

Tenacity: 

Streak: brownish, nearly white

Synonyms/varieties: manganosteenstrupine (Mn-rich variety)

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