Ultramafic rock but there are ultrapotassic and highly silica-under-saturated rocks with >18% MgO which can be considered "ultramafic". Ultrapotassic, ultramafic igneous rocks such as lamprophyre, lamproite and kimberlite are known to have reached the surface of the Earth. Although no modern eruptions have been observed, analogues are preserved. Most of these rocks occur as dikes, diatremes, lopoliths or laccoliths, and very rarely, intrusions. Most kimberlite and lamproite occurrences occur as volcanic and subvolcanic diatremes and maars; lavas are virtually unknown. Vents of Proterozoic lamproite (Argyle diamond mine), and Cenozoic lamproite (Gaussberg, Antarctica) are known, as are vents of Devonian lamprophyre (Scotland). Kimberlite
Latin Grammy Award for Best Rock Album Latin Grammy Award for Best Rock Album The Latin Grammy Award for Best Rock Album is an honor presented annually by the Latin Academy of Recording Arts & Sciences at the Latin Grammy Awards, a ceremony that recognizes excellence and promotes a wider awareness of cultural diversity and contributions of Latin recording artists in the United States and internationally. According to the category description guide for the 2012 Latin Grammy Awards, the award is for vocal or instrumental rock albums containing at least 51 percent of newly recorded material. It is awarded to solo artists, duos or groups. The accolade