There are six collectible gems on each floor in Luigi’s Mansion 3. In this guide, I’ll show you where to find all six gems on the 12F floor and tell you how to get your hands on them. You’ll need to unlock certain abilities before you’ll be able to collect some of these gems, so you may have to come back later on in the game.
Please note that some of the gems will appear clear rather than coloured in the screenshots seen below, this is because I had already collected them during my playthrough before creating this guide.
Gem #1 – Elevator Hall
On the far left side of the Elevator Hall, use the Super Socket to plug your vacuum in and suck up everything in sight, including the wall on the left (which will reveal a pipe) and the rug to your right. Sucking up the rug on the right will reveal a red X on the floor, and X marks the spot of course, so stand on top of it and perform a Burst (ZL + ZR) to get yourself the Blue Gem.
Gem #2 – Elevator Hall
Now summon Gooigi and slip through that pipe that you revealed on the left-hand wall before. Doing so will send him behind the bar, where you’ll find a golden globe sitting on the shelf. Use his vacuum to suck it up and fire it out into the main part of the Elevator Hall, then switch back to Luigi and suck it up with his vacuum. Walk over to the right hand side of the Elevator Hall and you’ll see three balls hanging in the near right corner. Fire the globe at the one furthest to the right and it’ll explode, spitting out a whole load of coins and the Yellow Gem.
Gem #3 – Grotto Lounge
Head into the Grotto Lounge. Just down the steps which are immediately on your left you’ll notice a skull holding the Clear Gem above you. To get it, use your Dark Light on the box underneath the skull and a jolly roger flag and a rope will appear. Use your vacuum to suck up the rope and then press A and the flag will raise, causing the skull to open its jaw and drop the Clear Gem.
Gem #4 – Beach
Head to the Beach and turn left as soon as you get into the room. Go just past the palm trees and you’ll see a statue on a small island just off the shore. Suck up a coconut from one of the palm trees and fire it at the statue and a bit of it will break off. Keep repeating this step until the statue breaks and a ghost appears. Defeat the ghost and you’ll get the Red Gem.
Gem #5 – Beach
Now head on over to the right hand side of the beach and off the screen, revealing an extra bit of beach. Stand on the shore on the right and use your Dark Light to reveal a bridge. Go over the bridge to a tiny island and use your vacuum to suck up the sand and find the Purple Gem.
Gem #6 – Beach
Now use your Dark Light at the top of the island to reveal another bridge which leads to another, slightly larger island. Use your vacuum to suck up all of the sand in the top right of the island to reveal a chest. Open this chest twice and on the second occasion the Green Gem will pop out.
And that’s it! Congratulations, you collected all six gems.