Black Agate Pendant Super-Silky and Glassy Free-Form ShapeHighly polished, glassy, Black Agate pendant with dynamic pattern measures 3 inches long by 1 7 8 inches wide by 1 5 inch thick. Dainty sterling silver bail. Black Agate meaning: Black Agate is primarily composed of chalcedony and quartz. This is the stone of the humanitarian. Theophrastus named this stone agate. He found it along the shore on Sicily. Most of the agate there is tan and white though. He was a Greek philosopher born 371 BC. He took over