General Information:
Chemical Formula:
Fe++3Al4(PO4)4(OH)6·2(H2O)
Composition:
(Molecular Weight = 793.43 gm)
Aluminum 13.60 % Al
Iron 21.12 % Fe
Phosphorus 15.62 % P
Hydrogen 1.27 % H
Oxygen 48.40 % O
Empirical Formula:
Fe2+3Al4(PO4)4(OH)6·2(H2O)
Environment:
Phosphate ironstones. Forms a series with souzalite.
IMA Status:
Approved IMA 1977
Locality:
Rapid Creek and Big Fish area, Yukon Territory, Canada.
Name Origin:
Named for Donald Herbert Groman (1922-), University of Toronto, Canada.
Physical Properties:
Cleavage:
[001] Indistinct
Color:
blue green.
Density:
3.13
Habits:
Radial - Crystals radiate from a center without producing stellar forms (e.g. stibnite), Aggregates - Made of numerous individual crystals or clusters., Bladed - Aggregates of thin la th-like crystals (e.g. kyanite).
Hardness:
4-5 - Fluorite-Apatite
Luminescence:
Non-fluorescent.
Luster:
Vitreous (Glassy)
Streak:
pale green
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