Merrihueite

Formula:  (K,Na)₂(Fe,Mg)₅Si₁₂O₃₀

Origin of name:  For C. Merrihue, American astronomer

Crystal system:  Hexagonal

Crystal class:  6/m 2/m 2/m

Twinning: 

Unit cell: a = 10.16, c = 14.32

Colour:  Greenish-blue

Diaphaneity: Transparent

Luster: Vitreous

Habit:  Grains, to 150 µm

Hardness: 5-6

Specific gravity:  2.87

Cleavage:  None

Tenacity: 

Streak: White

Synonyms/varieties:

Comments:  From a meteorite