From Bulbapedia, the community-driven Pokémon encyclopedia.
Sunburst Island (Japanese: ポンカン島 Ponkan Island) is located in the southwestern region of the Orange Archipelago. It is known for its high-quality glassblowing shops. People come from around the world to see them. It has a high quantity of crystal everywhere, making it a perfect place for crystal sculptors. It seems to not have a Pokémon Center, so this is probably not a suitable place for Pokémon Trainers.
The island is fairly large, and a smaller island is connected to the main island by a sandbar, but the path is only accessible when the tide is very low. It is a small island with a forest surrounding multiple entrances to the Crystal caves. A Crystal Onix that is immune to Water-type attacks dwells within the crystal caves.
Places of Interest
A street in the town area where people who make the glass sculptures sell their creations. It is like a bazaar.
The store where Mateo and Marissa sell their artwork of Pokémon Crystal sculptures. They also on occasion sell crystal vases and things like that. The owner uses a Charmeleon to help him make glass.
A place where the crystal sculptors can gather crystal here for their shops. There is a large lake in the middle where the Crystal Onix dwells.
Pokémon seen on Sunburst Island