Minecraft wiki entry for Model, associated text: Block models are used to depict all the blocks in the game, whereas item models are used to display the items in the players, hand, on their head (helmets and hats), on the ground, in the inventory, in item frames and on armor stands. As there are different variants of some blocks, block states are used to link these with the corresponding models. Each model and each block state has its own file, which is of the .json format. Even the icons used in the inventory are defined in these files.