About Clayton Quarry

Clayton Quarry began operation on February 17, 1947 and was purchased by CEMEX in 2005. Diabase – a volcanic rock – was being mined from the ground in the form of aggregates. These rocks and bits of sand and gravel add strength and stability to Bay Area projects and many of Contra Costa County’s roads. Today, Clayton Quarry continues to play a major role in providing aggregates for the region’s significant projects and economic growth. Having a local source of aggregate reduces regional truck traffic and air emissions.