Dioyudaoite

Formula:  NaAl₁₁O₁₇

Origin of name:  From locality; Diaoyudao Island, Taiwan

Crystal system:   Hexagonal

Crystal class:   6/m 2/m 2/m

Twinning:

Unit cell: 

Colour:   Colourless, light green

Diaphaneity:  Transparent

Luster:   Vitreous

Habit:   Thin tabular crystals 0.02-0.04 x 0.4 mm

Hardness:   7.6

Specific gravity:  3.30

Cleavage:   None

Tenacity: 

Streak: 

Synonyms/varieties:

Comments:   Crystals contain native chromium inclusions indicating a magnetic origin