Yaroslavite

Formula: Ca₃Al₂F₁₀(OH)₂.H₂O

Origin of name: locality, Yaroslav, Siberia, Russia

Crystal system: Orthorhombic

Crystal class: unknown

Twinning:

Unit cell: a = 8.74, b = 5.53, c = 4.51

Colour: White

Diaphaneity: Transparent

Luster: Vitreous

Habit: Spherical and oval aggregates, radiating fibrous structure

Hardness: 4-4.5

Specific gravity: 3.09

Cleavage: 1; pinacoidal, good

Tenacity: Irregular fracture (flat surfac, not cleavage)

Streak: White

Synonyms/varieties:

Comments:  Weakly fluorescent, SW-UV pale violet