gold
Samples that are the same size, but have different densities, will have different masses. Gold has a density of about 19 g/cm 3 . Pyrite has a density of only about 5 g/cm 3 . Quartz is even less dense than pyrite, and has a density of 2.7 g/cm 3 . If you picked up a piece of pyrite and a piece of quartz that were the same size, the pyrite would seem almost twice as heavy as the quartz.