Manganaxinite

Formula:  Ca₂MnAl₂BSi₄O₁₅(OH)

Origin of name:  From manganese and axinite

Crystal system:  Triclinic

Crystal class:  -1

Twinning: 

Unit cell: a = 7.16 Å, b = 9.2 Å, c = 8.95 Å, α = 91.8°, β = 98.5°, γ = 77°

Colour:  Honey yellow, brown, blue, colourless

Diaphaneity:  Transparent to translucent

Luster:  Vitreous

Habit: 

Hardness:  6.5 to7

Specific gravity:  3.32

Cleavage:  4; {100} good, {001}, {110} and {001} poor

Tenacity: 

Streak:  Uncoloured or pale

Synonyms/varieties:

Comments:  Series with ferro-axinite and with tinzenite