The gemstones used by The Star Carver are usually very high grade quartz; but, he has carved into and on ruby, topaz, aqua marine, peridot, opal, moonstone, and others. The stones he uses for internal or intaglio must have a window of flawless clear viewing. This is very hard to find in large raw crystal. usually, the larger stones are full of trapped water, air, relic xls. and debris that there is no line of sight anywhere.
John spent over 4 years attending the Tucson gem and mineral shows where he looked over hundreds of thousands pieces of gemstone quality crystals to pick a few dozen for his work.