The refractive oil used for jewelry identification is diiodomethane with molecular formula of CH2I2 and molecular weight of 267.87. It is a colorless, clear and yellowish heavy liquid, and it is also a commonly used analytical reagent. The general toxic invasion routes are inhalation, ingestion and percutaneous absorption, and it has anesthetic and stimulating effects at high concentration. It is recommended to wear suitable gloves and gloves when touching. ...