HEy Jimmy,
I've worked quartz quite a bit lately. It definitely is not as predictable as flint, but it does work. If you've got a big piece and it is grainy, the one tool you'll need is a hardwood billet.
I've tried working quartz with antler and it will work if the billet is heavy enough and the quartz is medium to high grade. But the grainier stuff really requires a hardwood billet. For some reason the hardwood is soft enough to send the energy thru the crystals, allowing you to peel off large, flat thinning flakes. But the trick is that you have to use a much larger billet than a comparable antler billet. Lots of hardwoods will work: oak, hickory, and osage orange are hard and also have plenty of weight, which is what you need. I always wondered how the ancients used quartz because it was so difficult to work...until I started using a hardwood billet. Then suddenly, it started working! You'll have to set up your edges well, and one trick is to bevel your edges so they are ABOVE centerline. I know it seems wrong, but quartz is very weak and brittle on the edges. If you hit an edge that's above centerline, there is more stone underneath the edge to support the blow, allowing large flakes to peel off. Edges that are below centerline have much less mass under them, causing them to crumble and not support the full power of the blow.
Quartz and especially quartzite respond really well to hardwood billets. Once you get your technique dialed in, you'll be amazed at what you can do with it. And quartz is SUPER sharp. I've got several points that are scary sharp and I really want to haft them on arrows and use 'em because that stuff is nothing to laugh at...
