Kimberlite garnets rich in chromium, are generally absent from most other igneous rocks, making them particularly useful as indicators for kimberlites. These indicator minerals are generally sought in stream sediments in modern alluvial material. Their presence may indicate the presence of a kimberlite within the erosional watershed that produced the alluvium. The geochemistry of Kimberlites is defined by the following parameters: Kimberlites are the most important source of primary diamonds. Many kimberlite pipes also produce rich alluvial or eluvial diamond placer deposits. About 6,400 kimberlite pipes have been discovered in the world, of those about 900 have been classified as diamondiferous,
Volcanic Rock (album) Music CD reissue Volcanic Rock (album) Volcanic Rock is the second studio album by Australian proto-heavy metal band Buffalo, recorded and originally released in 1973 on the Vertigo label. The album was stylistically a much harder, heavier and rawer release than its predecessor ("Dead Forever...") – marking a move away from the band's previous progressive rock influences, although retaining a psychedelic element to their sound. "Volcanic Rock" had been recorded effectively as a live-in-the-studio effort, with only vocal and additional guitar overdubs added later during the recording sessions. The album courted controversy with its cover artwork upon its release. Illustrated