Granite is igneous rock formed from the slow crystallization of magma below the Earth’s surface. It is composed mainly of quartz and feldspar with minor amounts of mica. It ranks 6 on the Mohs hardness scale for minerals.
Marble is a non-foliated metamorphic rock composed of re-crystallized carbonate minerals, most commonly calcite and dolomite. Because the main composition of marble is calcium carbonate (CaCO3), it is much softer than granite. It ranks 4 on the Mohs scale.
Quartz is a mineral that exists naturally in clusters. It does not form huge blocks like granite, marble or other types of natural stone. This means that it needs to be converted into another form, such as engineered quartz stone, to make it usable in such applications.
Engineered quartz is composed of crushed quartz mineral, unsaturated polyester, pigments and additives. Major brand names of engineered quartz include Caesarstone®, Samsung, Silestone, and Hanstone.
The manufacturing process begins with the selection of raw quartz materials. These are crushed and blended into the proper ratio of quartz, polyester resin and other additives. Because of its composition, quartz is generally harder than granite.
The mixture is compacted into slabs by a vacuum and vibration process at extremely high pressure. This process minimizes porosity and reduces water absorption. The slabs are then cured in a kiln at a temperature of 85⁰C for 30 minutes to attain the essential properties of resistance to staining and impact. The curing process may be accelerated by using ovens or steam. When curing is complete, the slabs are gauged, calibrated, polished and prepared for packing.