This is the most basic stone and most all purpose and one people purchase first.
I apologize, I should have discussed it first, but I was excited at getting certain stones and then seeing more in person, so I didn't discuss this basic stone first.  Quartz allows communication with guides and other planets. Clusters of Quartz can heal  other crystals. They lift spirits, alleviate depression, give strength, creativity and balance emotions. Thought to stimulate thought, many writers keep it by their computers/writing place. Chronic fatigue, hemorrhages, amnesia, and emphysema are thought to be treated by quartz. This crystal helps all chakras. I have heard Quartz is easy to program (set with intention). In my opinion, all stones are, it takes concentration and focus.
There is some debate over which crystals are related, ie. the same stone with different physical appearance, etc. Nothing is written in stone. haha, Get the joke? Try to enjoy the stone and focus on whether it helps you or not.