Yakhontovite

Formula: (Ca,Na)_0.5(Cu,Fe,Mg)₂Si₄O₁₀(OH)₂.3H₂O

Origin of name: for Liiia KKonstantinovna Yakhontova, Russian mineralogist, University of Moscow, a specialist in cobalt deposits.

Crystal system: monoclinic

Crystal class: unknown

Twinning:

Unit cell: a = 5.26, b = 9.108, c = 14, β = 90°

Colour: pistachio-green

Diaphaneity: Transparent

Luster: dull, earthy

Habit: equant to slightly elongated grains 0.1 to 10 micron in microcrystalline aggregates

Hardness: 2 to 3

Specific gravity: 

Cleavage: none

Tenacity: Conchoidal fracture

Streak: Light green

Synonyms/varieties:

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