Fissures occur naturally in many stone types. The term fissure is used commercially in the stone industry to describe a visible separation along intercrystalline boundaries. This separation may start and stop within the field of the stone or extend through an edge. A fissure differs from a crack in that it is a naturally occurring feature of the stone. All granites contain some degree of fissure. Some contain more than others. Fissures occur naturally in granite and are not a flaw. Pitting of the countertop surface, particularly in granite, is a commonly seen characteristic of natural stone. Granites are made up of several different minerals, each mineral having a different hardness. Granites contain quartz, feldspar, biotite, amphibole, ferrous titanium oxides, and other mineral combinations. On the Moh’s Scale, diamonds are the hardest mineral with a rating of 10. Quartz and feldspar have a hardness of 6.5-7 and are very durable. Biotite (small black minerals found throughout the slab) on the other hand is very soft (2.5) and flakes very easily. All true granites have biotite in their composition. Because biotite is relatively soft and flaky, the first few layers can be removed during the polishing process. The pits do not make the granite less durable or otherwise inferior, and do not in themselves qualify the slab for replacement. Pits are common in all granite and should be expected when dealing with a natural polished stone.