Quartzite is metamorphosed sandstone. There’s two kinds, meta and ortho. Meta is completely metamorphosed, ortho is partially and is knapable. The quartzite in our IL glacial tool is mainly meta from Canada. It’s roughly 1.7 billion yrs old. A wide range of colors. Quartzite is very workable and takes a nice polish. I’ve made many artifacts from it. These 3 are metaquartzite.