There are approximately 1.5 gallons of blood in an average human body. Average adult has 6 liters of blood (just under 1 and a half gallons), the average child has 1.5 liters, and the average infant has 500 mL of blood. Source(s): I'm a biology major.
Muscovite is another common mica mineral that has a single perfect cleavage similar to biotite and phlogopite. It also occurs in the same igneous and metamorphic rocks that biotite is found in. However, muscovite is much lighter in color than biotite, typically being colorless to white.
Some Rocks to Avoid. A few types of igneous and metamorphic rocks are not good choices for the rock tumbler. These include: 1  schist, gneiss and other rocks that contain significant amounts of mica. ( 2 micaceous rocks often split apart, shedding grains that spoil a polish). 3  rocks that are made up of easily dislodged grains.