Intangible Blocks (New Block Type)

Intangible blocks are blocks that normal players and mobs walk/fall straight through, but intangible mobs interact with as though they were tangible. I see them as being slightly transparent with a small glow to them. My current suggestions for subgroups of this block are faerie iron, faerie wood, and faerie stone. Faerie iron can be crafted into blocks and bars on its own, as well as tools, weapons, and boxes when combined with faerie wood. Faerie wood crafts basically the same as other wood blocks, and is only unusual in its color, texture, and interaction with ephemeral mobs. Faerie stone is the most decorative subset, and would have many variants with beautiful textures. All of these are just a start to the possibilities. If intangible blocks are added, there will likely be many more than the ones listed here!