This 3rd-5th century Roman or Byzantine rock crystal work found in a cistern in Carthage demonstrate
This 3rd-5th century Roman or Byzantine rock crystal work found in a cistern in Carthage demonstrates the quality of the arts of that great city as the Roman world became Byzantine. The Roman naturalist Pliny, describing it’s beauty, believed the crystal to come from snow. It was thought to protect against kidney aliments and other diseases. -- source link