INCI designates the key ingredients which make up a product. For a colorant such as Black Oxide the INCI is Oxide.
INCI itself is an acronym which stands for International Nomenclature of Cosmetic Ingredients. It is a system of names for waxes, oils, pigments, chemicals, and other ingredients of soaps and cosmetics based on scientific names and other Latin and English words. It exists as a way to inform the public on ingredients based on the guidelines for US regulatory bodies.