Surface plates are made from granite and offer a flat reference plane for QA, inspection, metrology, and setup applications. Granite surface plates are durable and rust- and corrosion-resistant and almost entirely nonmagnetic. Pink and gray granite surface plates have the highest quartz content which means more wear resistance and greater accuracy than other surface plates. Black granite surface plates are less absorptive of moisture, experience minimal thermal expansion, and are typically thinner, lighter weight, and provide less glare than pink and gray granite.