Granite is a natural rock mined from deep in the earth. The rock is cut into slabs and polished. Quartz is an engineered stone. Manufacturers grind natural quartz into small pieces and combine these with resins and color. The mixture is then pressed into slabs.
The pattern in granite is random and varies between slabs. ConsumerReports.org recommends viewing actual slabs at a stone yard, rather than samples. Because granite is a natural stone, it has tiny pits in the surface between the mineral crystals. Quartz has a more consistent pattern than granite.
Granite is porous and requires sealing at least once every three years. Quartz does not require sealing. Avoid the use of harsh chemicals and abrasive cleaners with granite and quartz. Use a few drops of dish-washing liquid on a wet towel to clean spills.
Granite is considered stain-resistant, but may become discolored from oils if not sealed, and may crack if hit by a heavy object. Granite is heat-resistant. Quartz is resistant to stains but can be damaged by exposure to high heat. Quartz doesn't withstand impact as well as granite.
Granite and quartz are comparable in price. Prices may vary depending on supply and demand. According to PermaStone Granite & Quartz, granite prices may also vary depending upon fuel costs from different mining sites.