You get the bucket back.

Charcoal works as well.

Middle emerald is a "Soul Crystal". Normal emerald does not work.

Those ghast tears are "Crystallized souls". They are mob drops. Emerald is the middle is a normal emerald, so are the rotten flesh.

You can replace smooth stone with cobblestone.

Base ingredient for making diamond armor and tools.

Same recipe as in vanilla, but uses "Infused iron ingot" instead. See "Furnace Recipes" for more info.

For making TNT