Varennesite

General Information: Chemical Formula:Na8Mn++2Si10O25(OH,Cl)2·12(H2O) Environment:As a primary, late-stage mineral in a sill. IMA Status:Approved IMA Locality:Demix-Varennes quarry, which lies between the villages of Varennes and Saint-Amable, in Vercheres County, Quebec Name Origin:For the locality.Physical Properties: Cleavage:[010] Good Color:pale brownish yellow or orange. Density:2.31 Diaphaniety:Translucent to transparent Habits:Tabular - Form dimensions are thin in one direction., Euhedral Crystals - Occurs as well-formed crystals showing good external form., Hardness:4 - Fluorite Luminescence:Non-fluorescent. Luster:Vitreous (Glassy) Streak:whiteMore details...