Obtaining a Sun Stone in Pokémon Go can be quite difficult if players don't know where to look. The Sun Stone is an evolutionary item introduced to the Pokémon series back in the second generation. The Sun Stone in Pokémon Gold and Silver allowed Pokémon like Gloom to get a secondary evolution. Normally, Gloom would just evolve into Vileplume when exposed to a Leaf Stone. However, using a Sun Stone will instead evolve it into Bellessom. As more generations were added to the Pokémon mythos, new evolutions were added using this item.
In Pokémon Go, only Gloom, Sunkern, Conttonee, and Petilil evolve using a Sun Stone, making them pretty rare to find. Although, they all still need to get more candy to evolve. For example, Sunkern will only evolve into Sunflora when it has a Sun Stone and has 50 Sunkern candy. In the mainline games, trainers need to trade their Sunkern holding a Sun Stone for it to evolve. The evolution process in Pokémon Go is much more streamlined and doesn't require a second player to do it.
To get a Sun Stone in Pokémon Go, trainers will need to keep spinning Pokéstops and Gym Stops. This is how players can get other evolutionary items like Dragon Scales, Upgrade, and Metal Coat. Although, there is only a 1% chance of finding a Sun Stone with every spin, making it somewhat difficult to find. The best thing to do would be to find a location where tons of PokéStops appear. Then, continue to spin them until a Sun Stone appears.
Using Sun Stones in Pokémon Go
There is also a chance Pokémon Go players can find a Sun Stone by completing Pokémon Go's Research Breakthrough task. Every day, trainers can collect up to one stamp by clearing Field Research tasks. After collecting seven stamps in total, the player will be rewarded with XP, rare items, and a Pokémon encounter with the chance of it appearing Shiny. For January, trainers will be rewarded with an Onix encounter. The reward Pokémon changes every month, but they are usually Pokémon that are fairly difficult to come by.
With Pokémon Go adding more Pokémon every few weeks, it's likely more Sun Stone evolutions will be added to the game. For example, when the Unova region was added to the game, it also added Cottonee and Petilil, two creatures from Pokémon Black and White that evolve using Sun Stones. Both are decent for taking on raid battles or participating in PvP. From the Pokémon's screen in the menu, the Sun Stone icon should be highlighted once the item is collected.
Pokémon Go is available now on iOS and Android.