What variety of stones/gems are there? I read someone said quartz, are there more than just quartz?

There are videos on YouTube you can watch that tells more about the mine.

Beryl ,aquamarine, smoky,clear and amethyst can be found

By no means do I know know everything about DH but of the quartz I do know that skeletal and amethyst and smokey are found there. I believe garnets, & aquamarine also.

It's mostly quartz. Lots and lots of smoky quartz, clear quartz, milky quartz, skeletal quartz. Much of the minerals are coated in yellow or black varnish. There are garnets, though they're unusual. We were told the occasioal aquamarine would pop up too. Amethysts are not what I'd call common, but they are definitely there for the taking. We saw some gorgeous examples of prior-found amethysts on our visit.

Quarts of many shades is most common, then skeletal then amethyst , its tricky. They can look like a regular stone until you soak them and clean off the packed clay. You can google search Diamond Hill pictures.. You should see some i recently posted there!