polygranular carbon

A carbon material composed of grains, which can be clearly distinguished by means of optical microscopy.
Note:
Industrial carbon materials (such as electrodes) are mostly polygranular, but special grades are agranular materials, such as glass-like carbon, carbon fibres or pyrolytic carbon. Such materials are covered by the term agranular carbon.
Source:
PAC, 1995, 67, 473 (Recommended terminology for the description of carbon as a solid (IUPAC Recommendations 1995)) on page 501