Mining rock and producing asphalt and concrete are part of a materials testing engineer's dream job. Graniterock is known for producing high quality construction materials for contractors throughout Northern California. Every shipment of aggregate, concrete and asphalt, and every project with cold in-place recycling, is backed by careful analysis and data that ensures specifications are met for each job. Graniterock has five testing laboratories across the San Francisco Bay Area that serve a vital role in the company’s quality control.