Recent researches on kimberlite and diamond geology

New developments since Wyllie's (1967) book include new discoveries (India, USSR); observations on zoning of xenoliths in pipes; a newmineral (amakinite) and several minerals reported from kimberlite for the first time; new data on composition and geochemistry of kimberlite; observations on maximum size, abundance, and banding of xenoliths. New isotopic ages (South Africa, U.S.A.) indicate that although xenoliths may give Precambrian dates, kimberlite minerals crystallized at times that fit field relations. Researches on diamond give data on included material (nitrogen, pyrrhotite, rutile) and new syntheses (one in the graphite stability field). A scheme for appraising diamond deposits is based on kimberlite composition and diamond morphology.