Marcasite The mineral marcasite, sometimes called white iron pyrite, is iron sulfide (FeS2) with orthorhombic crystal structure. On fresh surfaces it is pale yellow to almost white and has a bright metallic luster. It tarnishes to a yellowish or brownish color and gives a black streak. It is a brittle material that cannot be scratched with a knife. It typically forms under low-temperature highly acidic conditions.
Imitation Gold is a coating of metal whose color looks like 14k-18k gold, making jewelry more affordable but at the same time keeping the good quality. Imitation gold has a tint of red, and appears to have a reddish yellow hue.