I’d like to bring a limestone and other calcareous stones for Animal feed, please advise the HS Tariff code ?

Tariff code is 25.21. (with some exemptions).Cover only products which are in the crude state or which have been washed (even with chemical substances eliminating the impurities without changing the structure of the product), crushed, ground, powdered, levigated, sifted, screened, concentrated by flotation, magnetic separation, or other mechanical or physical processes (except crystallization), but not products which have been roasted, calcined, obtained by mixing, or subjected to processing beyond that mentioned in each heading.