Agrellite

General Information: Chemical Formula:NaCa2Si4O10F Composition:(Molecular Weight = 394.48 gm)Sodium 5.83 % NaCalcium 20.32 % CaSilicon 28.48 % SiOxygen 40.56 % O Fluorine 4.82 % F  Empirical Formula: NaCa2(Si4O10)F Environment:Alkalic igneous rocks of the Sheffield Lake complex. IMA Status:Approved IMA 1973 Locality:Kipawa River, Villieu Township, Temiscaming County, Quebec, Canada. Name Origin:Named for Stuart O. Agrell, British mineralogist, Cambridge University.Physical Properties: Cleavage:[110] Perfect, [110] Perfect, [010] Poor Color:white, grayish white, or greenish white. Density:2.88 - 2.9, Average = 2.88 Diaphaniety:Translucent Habits:Lath - Shaped like a small, thin plaster lath, tabular (rectangular) in shape., , Hardness:5.5 - Knife Blade Luminescence:Fluorescent. Luster:Vitreous - Pearly Streak:whiteMore details...