Some rare gems that work as gildings and or curios would be absolutely amazing. Could be another use for the jewelry skill where the gems have to be refined into cut gems using say... lore+masonry+dex/psy or some such. Just please don't make it take gold-beaters skins but rather jeweler's grit paper like:
http://www.esslinger.com/emery-cloth-sand-paper-9-x-11-each-choose-grit/This jeweler's grit paper could be made from parchment, sand and glue.
sand: maybe give us more ways to get sand as well such as grinding stones like quartz and sandstone in a windmill using a specialized tumbling drum
https://en.wikipedia.org/wiki/Tumble_finishing which could be another way of finishing the gemstones. Say put the gems into the drum, add some sand (which could be made in it as well) add water and let it work for a day or two.
For the gem types, if it's not too much work they could drop when mining specific types of rocks. For example amber would be found rarely when mining coal. Fossils/shells could be found when mining limestone/dolomite and marble. Granite would have some quartz gemstones like amethyst, geodes, calcite and pyrite formations. As it is, the curiosities you can find while mining are really.... bad to be fair and while I don't want to randomly find some impressive gild/curio they could be well balanced if they are a rare drop that then needs to be crafted using mid-late game gear into a high tier crafted curio.
heck, even if they aren't gilds/curios initially it'd be really cool to be able to decorate my house using them. Another idea would be new options for making rings, necklaces and such.
I could actually go on all day about gems/ores and new jewelry/mining abilities... Should I make a new thread to lay out all my thoughts in?
-Distant clown noises.