Purple chalcedony is microcrystalline form of silica that is very hard, dense and sometimes found with the most beautiful hues of purple and violet coloring (jewelry grade). It has been found in a handful of localities around the world. I have sourced material from Indonesia, Africa and here in the U.S. but I typically use only the top 1%-5% of material I purchase. I look for chalcedony with the best color which is ranges from violet to deeper hues of purple with good color saturation and few or no inclusions/flaws. The best material will also be translucent (not transparent) and will almost seem to glow as it tends to scatter incoming light. With the exception of purple sapphire or spinel, I have not seen another natural stone with this color of purple. Holly Blue is a form of chalcedony that was found in Oregon in an area that has been closed to mining for a number of years. Purple chalcedony is a natural material and as such, it may contain imperfections such as fortification lines or variations in color density as well as inclusions from the host material.