Aldermanite

Formula:  Mg₅Al₁₂(PO₄)₈(OH)₂₂^.32H₂O

Origin of name:  For Arthur Richard Alderman (1901-1980), Australian mineralogist, University of Adelaide, Adelaide, Australia

Crystal system:  Orthorhombic

Crystal class:  Unknown

Twinning:

Unit cell: a = 15.000 Å, b = 8.330 Å, c = 26.60 Å

Colour:  Colourless

Diaphaneity: Translucent to transparent

Luster:  Pearly

Habit:  Talc-like flakes

Hardness:  about 2

Specific gravity:  2.15 (calculated)

Cleavage:  None

Tenacity:

Streak: White

Synonyms/varieties:

Comments: Found as a secondary mineral in cavities in a brecciated metamorphosed sedimentary phosphate deposit; formed by alteration of fluellite.