Hi guys! Nice forum Steve! I just want to add to what I mentioned to Chris. I think that they still use HF on certain specimen types, but the prefered method is now mechanical vibrating tools with carbide tips, to break the brittle quartz free. Similar to how fosslis are prepared.
If the acid etching is used, they carefully prepare it with something like wax to cover parts they dont want altered. That keeps the remaining quartz natural looking, and not the dreaded white chalk look.