On my recent trip to the Tellus Museum at Cartersville, I found out that quartzite is a silica based mineral but it may be many colors depending on what the contaminates are. This huge amethyst is a type of quartzite. The purple color is linked to the presence of iron. What must the person who found this have thought! I cannot imagine the joy of such a beautiful find. It would be like someone in heaven sent you a special gift.
