This ultrabasic rock type is a source of niobium-rich garnets and the presence of phlogopite mica xenoliths in it necessitates transport times on the order of hours to days.
This ultrabasic rock type is a source of niobium-rich garnets and the presence of phlogopite mica xenoliths in it necessitates transport times on the order of hours to days. The most valuable form of this requires a low geothermal gradient with no thermal erosion during transport, and early miners called it "yellow ground" in reference to the limonite produced by its weathering. The hypabyssal equivalent of mica peridotite, its usual mode of occurrence is in pipes and its chief source in the United States is a crater near Murfreesboro, Arkansas. FTP, name this bluish igneous rock, the chief source of diamonds, named for a South African city.
This ultrabasic rock type is a source of niobium-rich garnets and the presence of phlogopite mica xenoliths in it necessitates transport times on the order of hours to days.
kimberlite (accept, but be surprised to hear, mica peridotite until "hours" is mentioned)