Quartz is the most powerful healing and energy amplifier that we have on earth. It holds, releases, absorbs and regulates energy. Used by doctors for acupuncture needles, added to a fuel line in a car it reduces fuel consumption. Quartz is also used in watches! Everyone should have a quartz cluster. They magnify the positives with all the other crystals. Used by all crystal healers and obviously it comes in a great many colours.
Variable depending on whether you want a cluster, stone or point.