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
Kimberlite tailings solution, which is subsequently neutralized with mineral acid to polymerize silica as insoluble precipitates. The products is useful in rubber, paints as abrasive etc. The experiments were conducted to investigate the sorption of arsenic from the groundwater onto kimberlite tailings in two phases - batch studies and column studies. In batch studies, the effects of different factors such as pH, adsorbent dose and adsorbent size on the performance of kimberlite tailings were investigated. Adsorption kinetics and equilibrium isotherm studies were also carried out. The adsorption capacity of kimberlite tailings was calculated as 0.25 mg/g of adsorbent. In column studies, the