Book 27, Question 81
Why do some rocks feel heavy for their size?
Different minerals pack different numbers of atoms and heavier atoms into the same space, which makes them dense.
Galena, a lead mineral, feels much heavier than quartz of the same size. Gold is even heavier. Comparing how heavy a sample feels, called heft, is a quick test. Scientists measure it as density or specific gravity by comparing the sample's weight with the same amount of water.