HTS code 2830.90.10.00 covers "Sulfides; polysulfides, whether or not chemically defined › Other › Zinc sulfide, luminescent grade having a purity of 99.99 percent or more by weight" under the US Harmonized Tariff Schedule. This is the official duty rate charged by US Customs when this product is imported into the United States, sourced directly from the U.S. International Trade Commission and refreshed daily.