Znucalite

Formula: Zn₁₂(UO₂)Ca(CO₃)₃(OH)₂₂.4H₂O

Origin of name: from composition (Zn, U, Ca)

Crystal system: Triclinic

Crystal class: 1 or 1

Twinning:

Unit cell: a = 12.692 Å, b = 25.096 Å, c = 11.85 Å, α = 89.08°, β = 91.79°, γ = 90.37°

Colour: White, light yellow, grayish yellow

Diaphaneity: Translucent

Luster: Silky

Habit: thin plates average 0.4 x 8 x 15 micron and grains forming porous coatings of saucer-shaped aggregates to 10 x 10 cm, encrustations, aggregates

Hardness:

Specific gravity: 3.01 to 3.1

Cleavage: 1; {010} perfect

Tenacity: 

Streak: White

Synonyms/varieties:

Comments: fluoresces yellow-green in both LW and SW UV-light, readily soluble in acid with effervescence