All rocks are made of 2 or more minerals, but minerals are not made of rocks.
A mineral is the same all the way through. That is one reason we speak of a sample or a specimen rather than a rock. There are about 3000 known minerals on earth. All rocks are made up of 2 or more of these minerals.
Quartz is one of the most common minerals in the Earth's crust. It is made up of silicon dioxide, otherwise known as silica. White sand is primarily made from quartz.
All micas form flat, book-like crystals that peal apart into individual sheets on cleavage planes. Crystals cleave into smooth flakes. Biotite is dark, black or brown mica.
Calcite is made of calcium carbonate. Generally white to clear, it is easily scratched with knife. Most seashells are made of calcite or related minerals. This is the 'lime' of limestone.