Metavoltine

Formula:  K₂Na₆FeFe₆(SO₄)₁₂O₂ ^. 18H₂O

Origin of name:  From Greek meta - after and voltine

Crystal system:  Hexagonal

Crystal class:  3

Twinning: 

Unit cell: 

Colour:  Yellowish brown to greenish brown, orange-brown

Diaphaneity:  Translucent

Luster:  Resinous

Habit:  Crystals tabular, hexagonal, minute; scaly or granular aggregates

Hardness:  2.5

Specific gravity:  2.40 to 2.51

Cleavage:  1; {0001} perfect

Tenacity: 

Streak: 

Synonyms/varieties:

Comments: