The Ol Doinyo Lengai volcano is unusual because its lava contains large amounts of this class of minerals. The rare earth ores at Bayan Obo are mostly found in rocks made from one member of this group. One classification for rocks with these minerals uses the presence or absence of micrite. That classification is known as the Folk system and contrasts with the Dunham system. One of its large subgroups is noted for having rhombohedral structures. 
The Ol Doinyo Lengai volcano is unusual because its lava contains large amounts of this class of minerals. The rare earth ores at Bayan Obo are mostly found in rocks made from one member of this group. One classification for rocks with these minerals uses the presence or absence of micrite. That classification is known as the Folk system and contrasts with the Dunham system. One of its large subgroups is noted for having rhombohedral structures. Dolomite is a magnesium containing member of this group which is found along with another member in Karst topography. They contain their namesake anion. For 10 points, name this group of minerals whose calcium type is found in calcite and limestone.
The Ol Doinyo Lengai volcano is unusual because its lava contains large amounts of this class of minerals.
carbonate minerals