Did kohl used to be called malachite?

No, kohl and malachite are not the same. Kohl is a traditional eye cosmetic made from various substances, including lead sulfide, used primarily in the Middle East and South Asia. Malachite, on the other hand, is a green mineral used for ornamental purposes and sometimes in pigments, but it is not used as a cosmetic in the same way as kohl. While both have historical significance, they refer to different substances.