Nierite

General Information: Chemical Formula:Si3N4 Composition:(Molecular Weight = 140.28 gm)Silicon 60.06 % SiNitrogen 39.94 % N  Empirical Formula: Si3N4 Environment:The grains probably formed by exsolution of Si and N from kamacite, perryite and schreibersite during parent-body metamorphism. IMA Status:Approved IMA Locality:In perchloric acid-resistant residues of three ordinary chondrite meteorites and one enstatite meteorite. Name Origin:For A. O. Nier (1912-1994), who was responsible for the now accepted measurement of the atmospheric N-isotope composition.Physical Properties: Cleavage:None Color:colorless, brown, or brownish red. Density:3.17 - 3.18, Average = 3.17 Diaphaniety:Transparent Habits:Granular - Generally occurs as anhedral to subhedral crystals in matrix., Tabular - Form dimensions are thin in one direction., Hardness:9 - Corundum Luster:Adamantine Streak:whiteMore details...