Maimechite

(named after the Maimecha River), igneous rock containing a significant amount of altered olivine glass. It forms when ultrabasic magma issues forth onto the earth’s surface or is intruded into fissures near the surface. Despite its extreme rarity, maimechite is of great interest because it points to the possibility of the formation of ultrabasic magma in the earth’s interior. The presence of glass in maimechite shows that during its intrusion this magma had temperatures of about 1700-2000°C, the point at which olivine melts.