HTS code 6815.91.00 covers "Articles of stone or of other mineral substances (including carbon fibers, articles of carbon fibers and articles of peat), not elsewhere specified or included › Articles of peat › Containing magnesite, magnesia in the form of periclase, dolomite including in the form of dolime, or chromite" 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.