Wu Collection, Lower Volume Radical: Stone (shí) Yu Kangxi Strokes: 19 Page 838, Entry 01 Tang Rhymes (Tangyun), Collected Rhymes (Jiyun), Rhyme Compendium (Yunhui), Correct Rhymes (Zhengyun): Pronounced yu (falling tone). Explanation from the Explaining Graphs and Analyzing Characters (Shuowen): A poisonous stone, found in Hanzhong. Classic of Mountains and Seas (Shanhaijing): On the western mountain known as Mount Gaotu, there is a white stone named yu, which can be used as poison. Commentary: If eaten, it causes death; if silkworms eat it, they grow plump. Additionally, in the Collected Rhymes (Jiyun): Pronounced yu. The meaning is the same.