Formula: NaCaBeSi2O6F
Origin of name: From Greek for white and to appear
Crystal system: Triclinic or orthorhombic
Crystal class: 222 or 1
Twinning: On {001 or {110}, polysynthetic or penetration (fourlings)
Unit cell: a = 7.42 Ǻ, b = 7.40 Ǻ, c = 9.99 Ǻ
Colour: White, greenish yellow, yellow, light green
Diaphaneity:
Luster: Vitreous
Habit: Crystals shot prismatic to tabular, pseudotetragonal; spherulitic
Hardness: 4
Specific gravity: 2/96 to 2.98
Cleavage: 3; {001} perfect, {100} and {010} distinct
Tenacity: Uneven; brittle
Streak: White
Synonyms/varieties:
Comments:
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