The Underground Biomes Constructs is a popular decorative modification which adds another 24 types of stone, 16 types of cobblestones and a whole host of different half-blocks, stairs or even buttons. All this you can get from the new biomes that are generated underground.
How to install Underground Biomes Mod
- Download and install Minecraft Forge
- Download a mod
- Unzip it and copy to C:\Users\User_Name\AppData\ Roaming\.minecraft\mods