Cejkaite

Formula: Na₄UO₂(CO₃)₃

Origin of name: After Jiri Cejak (1929-) for his numerous contributions to the crystal chemistry of U minerals.

Crystal system: Triclinic

Crystal class: 1 or 1

Twinning: 

Unit cell: a = 9.28, b = 9.295, c = 12.864, Z = 4; alpha = 90.293°, beta = 91.124°, gamma = 119.548°

Colour: Pale yellow to beige

Diaphaneity: Opaque

Luster: Vitreous

Habit: Pseudo-hexagonal, microscopic crystals

Hardness: 

Specific gravity: 3.67

Cleavage: 

Tenacity: 

Streak: Light yellow

Synonyms/varieties:

Comments:  Fluorescent, SW-UV weak yellow, LW-UV weak greenish yellow