Note:
The above definition of a homogeneous microstructure does not pertain to pores and structural components which may be visible by contrast differences in optical microscopy with polarized light. As a consequence, glass-like carbon with visible pores is still an agranular carbon. The same is true, for instance, for pyrolytic carbon with preferred orientation, such as conical or lamellar structures, visible in optical microscopy with polarized light. Use of the term agranular carbon is not restricted to bulk materials of a minimum size. Only particulate carbon should be excluded even if the isolated particles exhibit a homogeneous microstructure.