Illinois fluorite is famous for zoning, usually meaning that we see sharp phantoms of one color within another color. However, we do not often see such sharply delineated separation of colors as we have here, with one strong color ATOP another color and no gradient or phantom in between. It is a highly unusual aesthetic! The grape jelly, deeply colored purple cap on the yellow is just about 3 cm across and shocking in contrast. With really strong lighting, you can see that it is gemmy, and look through to the yellow cube faces beneath. Old material. Note the fluorescence, minimal but something (possibly due to oil inclusions).