Carbonado in the pores that are common in carbonados, they may have been introduced after carbonado formation. Inclusions of other minerals, rare or nearly absent in the Earth's crust, are found at least partly incorporated in diamond, not just in pores: among such other minerals are those with compositions of Si, SiC, and Fe‑Ni. No distinctive high-pressure minerals, including the hexagonal carbon polymorph, lonsdaleite, have been found as inclusions in carbonados, although such inclusions might be expected if carbonados formed by meteorite impact. Isotope studies have yielded further clues to carbonado origin. The carbon isotope value is very low (little carbon‑13
Flake tool the blow from the strike it distributed onto the rock in an even fashion, giving the fracture a radial appearance. The production of these lithic tools is only made possible due to their ability to fracture in this way. Examples of such materials include fine-grained materials, such as carbonado, volcanic rocks, obsidian, onyx, and types of glass. These would all be excellent materials for creating flake tools. Flake tools can teach us much about human history. Residue analysis can be done to learn what was processed by the flake tools. Use-wear analysis can give archaeologists an idea of what the