Keystone Countertops, located right next to Corinthian Marble and Granite, works with Corinthian to provide customers, private contractors, businesses and corporations with high quality counter tops. Marble and granite are the top choice when it comes to counter tops, and those are the materials that Keystone Countertops specializes in. The company has its own custom cutting garage in the back, where its many skilled employees can cut counters to any angle or dimension.