Xu Collection, Upper Volume Radical: Metal (jīn) Character: Tou Kangxi Dictionary strokes: 17 Page 1315, Entry 05 Pronounced tou. Broad Rhymes (Guangyun): Tou stone resembles gold. Comprehensive Geography of the Unified Empire (Yitongzhi): Daaermi is the ancient Danmeiliu State, which produces tou stone. Essential Criteria of Antiquities (Gegu Yaolun): Tou stone is the essence of natural copper. The modern variety, refined using smithsonite, is imitation tou. Cui Fang states: one catty of copper and one catty of smithsonite, when smelted, become tou stone. Authentic tou comes from the country of Persia; it resembles gold, and when heated, it turns red and does not blacken. Compendium of Materia Medica (Bencao Gangmu): If mercury is spilled on the ground, tou stone can be used to attract and collect it. Also a surname. Correct Meaning Guide (Zhengtitong): A minister of Southern Liang named Touwulun. Collected Rhymes (Jiyun): Also written in a variant form (dou).