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,
Grammy Award for Best Rock Instrumental Performance to Paul McCartney and the band Wings for "Rockestra Theme". From 1986 to 1989, the category was known as Best Rock Instrumental Performance (Orchestra, Group or Soloist). According to the category description guide for the 52nd Grammy Awards, the award is presented to artists "for newly recorded rock, hard rock or metal instrumental performances". As of 2011, Jeff Beck holds the records for the most wins, with six. Sting has received three awards, twice as a member of The Police -- although he had no part in the band's "Behind My Camel", the 1982 award winner which he did not