Effenbergerite

Formula:   BaCuSi₄O₁₀

Origin of name:   For Herta Effenberger, Austrian mineralogist

Crystal system:   Tetragonal

Crystal class:   4/m 2/m 2/m

Twinning:

Unit cell: 

Colour:  Blue

Diaphaneity:  Transparent

Luster:   Resinous, vitreous

Habit:   Plates to 0.1 x 8 x 8 mm

Hardness:   4 to 5

Specific gravity:   3.57

Cleavage:   2; {001} perfect, {110} poor

Tenacity: 

Streak:   Pale blue

Synonyms/varieties:

Comments:   Isostructural with gillespite and cuprorivaite; insoluble in most acids