Material properties of diamond these are known as ballas and are important to industry as they lack the cleavage planes of single-crystal diamond. Carbonado is a similar opaque microcrystalline form which occurs in shapeless masses. Like ballas diamond, carbonado lacks cleavage planes and its specific gravity varies widely from 2.9 to 3.5. Bort diamonds, found in Brazil, Venezuela, and Guyana, are the most common type of industrial-grade diamond. They are also polycrystalline and often poorly crystallized; they are translucent and cleave easily. Because of its great hardness and strong molecular bonding, a cut diamond's facets and facet edges appear the flattest and sharpest. A
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