Granite is a popular stone used for indoor and outdoor applications. Some granite have a different geological make up. Such as diabase, anorthosite,gabbro and diorite. These granite are some of the hardest of natural stones. They offer a very high level of resistance to scratching and abrasion. The dominant minerals in granite’s are resistant to chemicals that you would find in a residential setting but may have minerals that are vulnerable to certain acids.
Granite has naturally occurring fissures. A fissure is a natural fracture or break in the stone which may have a mineral bearing material. A fissure is different from a crack because it is naturally occurring in the stone that might be found in other parts of the slab or on other slabs from the same bundle.
Pitting in granite is a common characteristic. Granite’s are made of many different minerals. The minerals have different levels of hardness. Granite’s contain ferrous, biotite, amphibole, feldspars, quartz and a few other minerals.
Diamonds are the hardest mineral on the mohs scale with a rating of 10. Feldspar and quartz have a hardness of 6.5 to 7 and are extremely durable.
Biotites are small minerals that form throughout the slab but it is very soft and flakes easy.
All granite’s have biotites. Since biotites are very flaky. The first couple of layers is often removed when polishing causing pits. Some granite’s have more biotites than others. The higher the biotite content, the more pits it will have. Most polished stones will have pits depending on the amount of biotites. Pits will not make the marble weaker. Pits are common in all granite’s and should be expected with a polished natural stone.