Nylium is a variant of netherrack that is naturally generated in the Nether. It has two distinct variants: warped nylium and crimson nylium. These variants spawn in completely different biomes.
Both crimson and warped nylium blocks (via screenshot)
Nylium is generated naturally in the Nether. Players can pick them up by simply breaking them with a pickaxe that is enchanted with silk touch; otherwise, it is dropped as netherrack. When mined without a pickaxe, nothing is dropped. Players have a small chance (22.8%) of finding nylium blocks inside a hoglin stable chest in a bastion remnant.
Crimson nylium found in the Nether (via screenshot)
Nylium is similar to grass and mycelium blocks. They are used most commonly to grow mushrooms, huge mushrooms, fungi, and huge fungi. Fungi and mushrooms can be grown into huge fungi and huge mushrooms using bone meal, though they must be placed on the same type of nylium, or the bone meal will not even be consumed. They are also the only blocks on which roots can generate naturally.
Growing roots and fungi on crimson nylium (via screenshot)
Nylium blocks are similar to grass blocks but can only be found in the Nether. They can be used to grow roots, fungi, and mushrooms. You do need the silk touch enchantment on your pickaxe if you want to pick up nylium blocks.
A. Nylium blocks only drop when mined with a pickaxe with silk touch.
A. No, nylium cannot be made by players through the crafting table or furnace
A. Crimson nylium can only be found in the crimson forest biomes.