Metazellerite

Formula:  Ca(UO₂)(CO₃)^. 3H₂O

Origin of name:  From Greek - after and zellerite

Crystal system:  Orthorhombic

Crystal class:  mm2 or 2/m 2/m 2/m

Twinning: 

Unit cell: a = 9.718, b = 18.226, c = 4.965

Colour:  Chalky yellow, lemon-yellow, pale yellow

Diaphaneity: Translucent

Luster:  Dull, earthy, chalky

Habit:  Fibrous and hairlike, in pincushion clumps

Hardness:  ~ 2

Specific gravity:  3.414

Cleavage:  None

Tenacity: 

Streak: Yellow white

Synonyms/varieties:

Comments:  Radioactive. Dehydration product of zellerite (5H₂O to 3H₂O in metazellerite)