Raw minerals for the untitled Cosmic Horror game. I'm going for flexibility right now. The current target is a modern (not necessarily high end, but modern) desktop machine, but it's quite possible I'll be working with other platforms in the future; so I'm starting high-LoD and working my way down. Some of these are post-decimation, some are not. For invariably complicated models, I find 300 faces to be a reasonable target to go for; further reduction tends to be geometrically destructive in a noticeable way, so I wait until I know I need it.
The geode was definitely the hardest one; I actually tried to remesh it before I was comfortable with a decimation, simply because of all of the intersecting geometry in the internal crystals. Ultimately, though, I'm not 3D-printing it, I'm building a game; and that was taking much too long. I could make better use of my time dirtying up the outer shell.