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 Song Latin Grammy Award for Best Rock Song The Latin Grammy Award for Best Rock Song is an honor presented annually at the Latin Grammy Awards, a ceremony that recognizes excellence and creates a wider awareness of cultural diversity and contributions of Latin recording artists in the United States and internationally. The award is reserved to the songwriters of a new song containing at least 51% of the lyrics in Spanish. Instrumental recordings or cover songs are not eligible. Songs in Portuguese may be entered in the Brazilian field. The award has been given every year since the 1st Latin Grammy