I just realised that I have never seen or used it, neither crude oil of course, but there are more variants of it than this natural mineral that powers a lot of the world.
For a good bit of my teens, I lived in an active coal mining town. It was everywhere. People loved grabbing some and making "coal gardens", where you leave a few good sized chunks in water and let the minerals accumulate. Can be rather pretty.
Coal can also be used as a craft, not uncommon to find carved coal statues in tourist areas that have a history as a mining town.
I looked up "coal garden" and it unlocked a memory from my childhood. I think my older sister had a science experiment type of toy that grew crystals like that.
They're not uncommon among the other "Crystal/Mineral Aquarium" experiments! They can grow some stunning structures over time, but moving them without damaging the growth can be a bit of an issue.