General Information:
Chemical Formula:
(Fe+++,Al)24Si4O43(OH)2
Composition:
(Molecular Weight = 2,116.93 gm)
Aluminum 2.55 % Al
Iron 58.04 % Fe
Silicon 5.31 % Si
Hydrogen 0.10 % H
Oxygen 34.01 % O
Empirical Formula:
Fe3+22Al2Si4O43(OH)2
Environment:
Deeply weathered granite.
IMA Status:
Approved IMA 1981
Locality:
Bennachie car park, 7 km NW of Inverurie, Aberdeenshire, Scotland.
Name Origin:
Named for the Macaulay Institute for Soil Research.
Physical Properties:
Cleavage:
[001] Good
Color:
blood red.
Density:
4.41
Habits:
Earthy - Dull, clay-like texture with no visible crystalline affinities, (e.g. howlite)., ,
Luster:
Earthy (Dull)
Streak:
light red
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