ploof-pack/faithless/assets/minecraft/models/block/polished_blackstone_slab_top.json

{
  "parent": "block/slab_top",
  "textures": {
    "bottom": "block/polished_blackstone",
    "top": "block/polished_blackstone",
    "side": "block/polished_blackstone_slab_side"
  }
}