@geology_earth

#Magnesioferrite is a #magnesium #iron oxide #mineral , a member of the #magnetite series of #spinels . Magnesioferrite crystallizes as #black metallic #octahedral #crystals . It is named after its chemical composition of magnesium and ferric iron. The density is 4.6 - 4.7 (average = 4.65), and the diaphaniety is opaque. Occurs as well-formed fine sized crystals or massive and granular. Its #hardness is 6-6.5. It has a #metallic luster and a dark red streak. It occurs in fumaroles, as a result of combustion #metamorphism and #coal seam fires, in glass #spherules related to #meteorite impacts, and as accessory phase in #kimberlites and #carbonatites . It has been reported from Vesuvius and Stromboli, #Italy . #US #USA #canada #Russia #Brazil #America #Uk