This all started as a project focused on overhauling the nether to make it a more interesting place to explore. But now it's spiraled out to include its own mini-mod, Crystal Caves, which spawns small and large crystals in caves that you can do a lot of neat things with.
I'm not really sure what direction to that this project in, whether that be a biome-cave overhaul, a nether overhaul, or a new dimension mod entirely, so any suggestions or advice would be welcome.
Small and large crystals will now spawn in caves and the nether. Crystals glow with the same light as redstone, and drop Crystal Shards when broken. Crystal shards can be used for all sorts of nifty things.
Here you can see several small crystals, plus the smallest size of "big" crystal:
Crystal shards can be crafted into a variety of things...
Crystal tools can break the same blocks as iron tools, are slightly faster than iron tools (but slower than diamond) and are as enchantable as gold tools, but their durability is between iron and stone. Still, it's basically a much more useful version of gold tools, since they last so much longer.
Crafted like so:
Crystal Bone Tools:
Crystal Bone tools are crafted with bones instead of sticks. This doubles their durability, so that they now have 150 more uses than iron.
Crystal Glass (and Crystal Glass Panes):
When smelted, crystal shards harden into shatter-resistant crystal glass, which has the same blast resistance as stone. It will also drop itself when broken, without needing the Silk Touch enchantment. Sweet!
Glows slightly, like other crystals, but other than that it has no real use besides storage. Sure looks pretty, though.
(Crystal Block is on the left, raw crystal is on the right. Raw crystal can only be harvested by using Silk Touch on a large crystal)
This is the mod that I originally had planned, before I got side-tracked by crystals. There aren't any actual biomes yet, but I have made a variety of things to put in those biomes when the time comes. Here's a preview:
A new type of mushroom that has a faint glow and grows into Giant Glowshrooms. They can be crafted into Luminous Goo, which currently has no purpose.
See those blue-and-pink cabbage flowers in the screenshot above? Yeah, don't touch them. They'll poison you. But if you're careful, you can break them to get a Poison Bulb.
The Meaning of Life, the Universe, and Everything.
This is awesome! I'm already using crystal caves, and I love it because it feels like a natural extension to vanilla (plus the textures are beautiful as to be expected), but I hadn't realized it was part of an overarching idea. Personally I'm loving the idea of a nether overhaul, considering how barren it's always felt. If you keep the blue crystals in the overworld, you could add a "stronger" version in the nether for progression. The flowers and giant glowing mushrooms are amazing! It would be seriously cool to see similar elements as underground biomes, or unique cave features in the overworld. In any case, good luck! I'm looking forward to mods you make in the future.