Anvil

Anvil is a block. Unlike in vanilla Minecraft, it cannot be damaged by using it too much, but still can be damaged by falling.

Location
One is found in the Village near the Blacksmith or in front of the Gold Mine, or crafted and placed in the Player’s island with the normal vanilla recipe.

Anvil Uses
Anvil uses are a vanilla minecraft mechanic that used to be in SkyBlock anvils, however it was removed in the enchanting update. The more anvil uses an item had, the more expensive it was to add another enchantment. Glitches were found and abused to remove anvil uses and reduce the cost of enchanting tools.

Combining Enchanted Books
The Anvil is often used to combine low-level Enchanted Books to increase their level. It takes two of the same level to increase, so it is not possible to get a level V book from 5 level I books. Instead, it would take a total of sixteen level I books to create a level V book. This does not work for all levels, however, as many high-level enchantments (usually level VI or higher) are obtained from Dungeons, Experiments, or the Dark Auction.

Combining Tools
Two items of the same type can be combined to add their enchantments, just like Vanilla Minecraft. However, unlike Vanilla Minecraft, it does not increase durability, because there is no durability in Skyblock. For this reason, it is not recommended to combine tools of a high rarity because it is usually much cheaper to just add more enchantments than to get a second tool of the same type.

Scam Prevention
Unlike Vanilla Minecraft, items cannot be renamed. This is to prevent people renaming cheap tools to more expensive tools that look similar and selling it on the Auction House (like renaming a wooden hoe, which is worth about 5 coins, to a Mathematical Hoe Blueprint, which can sell for over a million).

Bugs
There is currently a bug where if lagging and you spam shift click an item, you can sometimes obtain a barrier item the same as the one in the anvil.