Velvet is a type of woven tufted fabric in which the cut threads are evenly distributed, with a short dense pile, giving it a distinctive feel. Velvet can be made from either synthetic or natural fibers.
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.