Orlymanite

General Information: Chemical Formula:Ca4Mn++3Si8O20(OH)6·2(H2O) Composition:(Molecular Weight = 1,007.87 gm)Calcium 15.91 % CaManganese 16.35 % MnSilicon 22.29 % SiHydrogen 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 brownMore details...