Chukhrovite

Formula:  Ca₃(Ce,Y)Al₂(SO₄)F₁₃ ^. 10H₂O

Origin of name:  For F. Chukrov, Russian mineralogist

Crystal system:  Cubic

Crystal class:  4/m -3 2/m

Twinning:

Unit cell: a = 16.8

Colour:  Colourless, white

Diaphaneity:  Transparent to translucent

Luster:  Vitreous when transparent, weakly pearly

Habit:  Crystals small

Hardness:  3

Specific gravity:  2.27 to 2.40

Cleavage:  1; octahedral indistinct

Tenacity: Brittle

Streak: White

Synonyms/varieties:

Comments:  Two distinct species with the extensions -(Ce) and -(Y) indicating the predominant rare earth cation in the formula