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 the What writes: "Over the course of many years, Dave and I have collaborated to tell my story... I told [him] what I knew and what I could remember, and from that material he created this work of art." The book is typical of Eggers' style: blending non-fictional and fictional elements into a non-fiction novel or memoir. By classifying the book a novel, Eggers says, he freed himself to re-create conversations, streamline complex relationships, add relevant detail and manipulate time and space in helpful ways—all while maintaining the essential truthfulness of the storytelling. However, not all critics were impressed. Lee Siegel sees