|4 Johto badges|
To begin the Olivine City Lighthouse Quest, talk to Jasmine located on the top floor of the Olivine Lighthouse. Jasmine wants to restore the lighthouse to its former glory as a beacon for incoming ships once again. In order to do so she wants you to get her the Reflector Disc and the Power Cell. Only after completing this quest you’ll be able to challenge Jasmine in the Olivine City Gym for the Mineral Badge.
Make your way though the Olivine Lighthouse and talk to Jasmine on the top floor.
The Reflector Disc, one of the items Jasmine asks you to get her, can be found inside one of the “orange crates” (the things that look a lot like shipping containers) inside the lighthouse itself. There is no way of telling in which crate the Reflector Disc is located, so you’ll have to interact with all of them.
For the next and final quest item, the Power Cell, you have to go to Ecruteak City and meet up with Electrician Ferros. Electrician Ferros’ house is the one on the right of the Ecruteak City Gym. Ferros is willing to part with the Power Cell, but in exchange he wants you to get him a Secret potion for his Ampharos from the Pharmacy in Cianwood City. Ferros will also “reward” you with two transportation tickets so that you’re able to take the Ferry from Olivine City to Cianwood City
Once you’ve made your way to Cianwood City enter the pharmacy, the house with the sign next to it, and talk to the clerk. He’ll say that he’ll make you the Secret Potion, but that it’ll take some time before it’s finished. This is the game’s way of telling you that you need to beat Chuck, the Cianwood City gym leader first. After you’ve done that the Secret Potion will be ready. Beware: the Secret Potion isn’t a quest item but an ordinary potion, so it could happen that you’ll use it by accident. Don’t worry though, cause you can get a new one by talking to the clerk again.
With the Secret Potion in your backpack you can go back to Engineer Ferros in Ecruteak City, and he’ll trade you his Power Cell for it, since he no longer needs it. All there’s left to do is to give both items to Jasmine at the Olivine Lighthouse.