Orlymanite

General Information:
 Chemical Formula:
Ca4Mn++3Si8O20(OH)6·2(H2O)
 Composition:
(Molecular Weight = 1,007.87 gm)
Calcium 15.91 % Ca
Manganese 16.35 % Mn
Silicon 22.29 % Si
Hydrogen 1.00 % H 
Oxygen 44.45 % O 
 Empirical Formula:
Ca4Mn2+3Si8O20(OH)6·2(H2O)
 Environment:
Part of a vein assemblage. One specimen known.
 IMA Status:
Approved IMA
 Locality:
Wessels mine, Kalahari manganese field, Cape Province, South Africa.
 Name Origin:
Named for Orlando P. Lyman (1903-1986), founder of Lyman House Memorial Museum, Hilo, Hawaii.
Physical Properties:
 Cleavage:
[0001] Perfect
 Color:
dark brown.
 Density:
2.7 - 2.8, Average = 2.75
 Diaphaniety:
Translucent
 Habits:
Rosette - Bundled tabular aggregates resembling rose flower petals., Platy - Sheet forms (e.g. micas).,
 Hardness:
4-5 - Fluorite-Apatite
 Luster:
Vitreous (Glassy)
 Streak:
light brown
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