Crack open your own Moroccan quartz geodes. Available in three sizes, most contain hollow quartz cavities however some are completely solid quartz. 
HOW TO OPEN: for the cleanest break use a hammer and chisel. Place the chisel across the flat face of the geode and hit it progressively harder until it cracks. Some can be tougher than others especially ones filled with solid quartz. If this is the case hitting it hard with just a hammer will eventually smash it open. They can also be cut open if you have an appropriate saw for cutting rock.