This mod adds a whole bunch of alternate diamond-level tools and armor to fill the gaping hole in my heart that ony colored armor can fill
I recommend using my diamond and emerald texture match resource pack alongside this mod
This pack adds ores, armor, and tools for the following gemstones (Emerald does not have a modded ore, obviously):
Ruby - Spawns in savanas, deserts, and mesas
Spinel - Spawns in unique/flowery biomes
Topaz - Spawns in jungles
Emerald - Spawns in mountains (The default)
Sapphire - Spawns in Oceans, Ice/snowy biomes, and any biome with spruce
Amethyst - Spawns in plains/forests (Has its own special ore due to the commodity of regular amethyst)
All ores spawn in the deep dark
I may add horse armor, but it's not very high on my priorities list.