A Sun Stone is an evolution stone that can be obtained by crafting, as a drop from boss Pokémon, or from PokéLoot chests. It can be used for the following evolutions:
Sun Stones can be obtained by crafting or as tier 2 special drops.
Sun Stones can be crafted with Sun Stone shards, found as a drop from wild Solrock or by using Forage on stone-based blocks with a Fire-type or Fairy-type Pokémon.
Besides being used for evolution, Sun Stones can be used to craft Sun Stone tools and Sun Stone armor.