The name Onyx has sometimes been used, incorrectly, to label other banded lapidary materials, such as banded calcite found in Mexico, Pakistan, and other places, and often carved, polished and sold.This material is much softer than true onyx, and much more readily available. The majority of carved items sold as "onyx" today are this carbonate material.Natural stone is made up of several different minerals,each having different degrees of hardness. Some of the softer or flakier minerals on the surface are removed during the polishing process, causing pits. These pits do not make the stone less durable or inferior. As a natural product, the slab may contain naturally occurringimperfections.These characteristics, including color variations, irregular markings, fissure lines (which appear as hairline cracks), and polishing swirls all add to the beauty and rugged elegance that is normal with natural stone.