Bort (or Boart) is the name given to impure crystals or fragments useless for jewels; it is also applied to the rounded crystalline aggregates, which generally have a grey colour, a rough surface, often a radial structure, and are devoid of good cleavage.
Both bort and carbonado seem to be really aggregates of crystallized diamond, but the carbonado is so nearly structureless that it was till recently regarded as an amorphous modification of carbon.
The employment of powdered bort and the lapidary's wheel for faceting diamonds was introduced by L.
For rock drills, and revolving saws for stone cutting, either diamond, bort or carbonado is employed, set in steel tubes, disks or bands.
PIERRE EDMOND TEISSERENC DE BORT (1814-1892), French writer and politician, was born at Chateauroux on the 17th of September 1814, and entered the civil service after the completion of his education at the Ecole Polytechnique.