1) Natural Stone
Granite – Granite is an igneous, magma-formed rock that is generally made up of quartz, feldspar and mica. These minerals combine in varying percentages that account for the color, veining and crystallization patterns that make each granite deposit, — and therefore each customized countertop, — unique. Other minerals, such as magnetite, pyrite, garnet and hematite can occur in much smaller amounts, and as such, it is these different combinations that create the wide range of granite varieties that are available throughout the world. Granite is next to diamonds in hardness and is therefore highly durable. Granite countertops can withstand rugged handling, high temperatures and moisture; they also resist scratches and cracks and are therefore long lasting if sealed properly.
Marble – Marble is a rock resulting from metamorphism of sedimentary carbonate rocks, most commonly limestone or dolomite rock. The marble rock is typically composed of an interlocking mosaic of carbonate crystals. Pure white marble is the result of metamorphism of a very pure (silicate-poor) limestone or dolomite protolith. The characteristic swirls and veins of many colored marble varieties are usually due to various mineral impurities such as clay, silt, sand, iron oxides. The high carbonate content causes marble to be very sensitive to acid. As such marble is not recommended for kitchen countertops as even mild fruit acids will permanently etch the surface.
Quartz – Quartz countertops are an engineered man made stone product made from quartz – around 93 percent quartz to be exact. Quartz is a durable and abundant gemstone. To produce countertops, ground quartz is mixed with coloring pigments and binding agents. Quartz countertops are very durable, resistant and never require sealing. Although very durable, some special care has to be taken in order to keep the countertops looking like new. The pigments and binding agents used to produce the countertops are sensitive to high heat and UV rays. Very hot pots and pans should not be placed directly on the countertops and quartz should not be used in applications where it will be under direct sunlight.
2) Origin of slabs
Major world producers – Some of the world’s largest granite and marble producers are Italy, Turkey, China, Namibia, India and Brazil.
Producing slabs is a multi step process that begins with the mining of raw blocs.
- Mining– Huge chunks of granite are mined from deposits in the earth for the specific purpose of producing granite slabs. Chunks are either cut out of granite deposits or blasted out using explosives.
- Process– A chunk of granite will be extracted from a deposit site and cut into a large block. That block is then placed in a slicing machine that uses a special diamond-tipped blade to cut through the granite.
- Dimensions– Granite blocks that have been mined are most often cut into ¾ -inch or 1 ¼-inch slabs. Granite slabs are traditionally cut into sections 112+ inches long by 65+ inches wide.
- Shipping– Part of the reason that granite slabs are cut to specific lengths is to make it easier to ship them in mass quantities. Slabs are bundled together in groups of 8 to 10. Several bundles can fit into a traditional train or shipping container.
2) Granite and Marble Quality
Buying granite is a bit like buying a diamond. Deciding you want a 1 carat diamond is only the first step as they are not all made equal.
- First Choice Quality– this is what the name says, the finest quality ever. The polishing process is free of any visual defects and the surface will be high gloss. With first choice quality granite the amount of waste material is lower.
- Commercial Quality– typically with this grade the granite and marble slabs will not polish quite as well and obvious visual defects such as blotches or small natural hairline cracks will be present.
- Second Quality– this grade of granite typically is used for larger contract or larger projects where the granite slabs are to be cut into smaller modules. The granite and marble will have several repairable natural defects along with blotches.
Pits and fissures:
Often granite can have pits on the surface due to the fact that granite is a crystalline structure and spaces between the various mineral crystals can occur. These pits are not as noticeable when you look at a larger piece because the overall appearance is polished and mirror-like. Granite countertops sometimes have natural fissures as well, which may look like cracks, but are not structural defects and are a naturally occurring result of the immense heat and pressure which formed the granite millions years ago. These characteristics are part of the natural beauty of stone and will not impair the function or durability of the material.