Volcanic eruptions usually originate from a depth of approximately 30 miles underground, while a diamond-spewing volcanic eruption sucks magma ore from more than 90 miles deep. Diamonds in the rough are mined in several forms before being examined and polished into a variety of spectacular shapes. The principle rough diamond shapes include;
octahedron

dodecahedron

cube

rhombododecahedron

As the hardest material on earth, diamonds inevitably fulfill many industrial needs, for which 80% of the planetary diamond supply is used while only 20% of the world diamond production is gem quality, suitable for polishing and wearing. The diamond industry uses a number of rough identification terms such as: 'Spotted' stones which have inclusions that can be either removed or partially concealed by skillful cutting; 'Plats' which are usually macles trimmed into rose-cut diamonds; 'Sands' weigh less than 0.10cts; 'Common Goods' are very poor quality while 'Rejected Stones' are eliminated completely. Although magma doesn't contain diamonds, its inherent volcanic force snatches them as it clumsily erupts, scattering embedded rocks over mountainous terrain.