Carbonado typical gem diamonds. Lead isotope analyses have been interpreted as documenting crystallization of carbonados about 3 billion years ago. The carbonados are found in younger sedimentary rocks. Mineral grains included within diamonds have been studied extensively for clues to diamond origin. Some typical diamonds contain inclusions of common mantle minerals such as pyrope and forsterite, but such mantle minerals have not been observed in carbonado. In contrast, some carbonados do contain inclusions of minerals characteristic of the Earth's crust: these inclusions do not necessarily establish formation of the diamonds in the crust, however, because while these obvious crystal inclusions occur
What Is This? What Is This? What Is This (known prior to 1980 as Anthym) was a rock band that originated in Fairfax High School in California and would play numerous shows along the coast of California. It was formed by guitarist Hillel Slovak, drummer Jack Irons, vocalist Alain Johannes, and bassist Todd Strassman. Originally named Chain Reaction, the band would later change its name to Anthem, then later to Anthym (as there was already a band using the former moniker), and then finally to What Is This, which was a tongue-in-cheek reference to the reaction they usually received from first-time listeners. During