High Quality Content by WIKIPEDIA articles! Soapstone Ridge is a mafic-ultramafic geological complex located in the Piedmont region, south-east of Atlanta, Georgia on a 25-square-mile (65 km2) area in DeKalb County and neighboring Fulton, and Clayton Counties. Many archaeological sites, including Late Archaic quarry sites dated between 600 BCE and 1500 BCE, occur on Soapstone Ridge. At least 17 quarry sites and 23 workshops sites have been located on Soapstone Ridge.