Danalite

Formula: Fe₄Be₃(SIO₄)₃S

Origin of name:  For James Dana, American mineralogist

Crystal system:  Cubic

Crystal class:  -43m

Twinning:

Unit cell:

Colour:  Gray, lemon yellow, yellowish pink, red, reddish brown, brown

Diaphaneity:

Luster:  Vitreous to greasy or resinous

Habit:  Crystals octahedral or dodecahedral; massive granular

Hardness:  5.5 to 6

Specific gravity:  3.31 to 3.46

Cleavage:  1; {111} trace

Tenacity:

Streak:

Synonyms/varieties:

Comments:  Series with genthelvite and with helvite