(3) Chromium (III) oxide is the inorganic compound of the formula Cr2O3. It is one of the principal oxides of chromium and is used as a pigment. In nature, it occurs as the rare mineral eskolaite. Chromium Oxide Green, also known as chromium sesquioxide or chromia, is one of four oxides of chromium. It is commonly called chrome green when used as a pigment. When it is added to glass it gives green colour to the glass.