Hollandite Black Silvery-gray 4-6 color; may occur as rounded masses 3. METALLIC luster, YELLOW color A. Does not readily leave mark on paper but can be scratched by ordinary pocket knife Chalcopyrite Greenish black Brass-yellow or 3½-4 golden-yellow color that may tarnish and show rainbow-like colors; commonly massive; notice streak Gold Shiny golden Shiny yellow 2½-3 yellow color; extremely heavy; flattens when hit with hammer; notice streak B. Cannot be scratched by ordinary pocket knife Pyrite Black, greenish Shiny, pale 6-6½ black, or golden-yellow or brownish black brass-yellow color that may tarnish; occurs as grains, as masses, or as cubes or other crystal shapes; notice hardness and streak 4. METALLIC or SUBMETALLIC luster, BROWN color