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 5F 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 – 501 Balcony
As soon as you come out of the elevator, perform a Suction Shot on the couch blocking the corridor to the left with both Luigi and Gooigi, as you’ll need their combined strength to shift it. Once that’s out of the way, a few steps down the corridor you’ll notice that there’s no door where there should be one according to your map, but you should be able to see a feint outline of one. Shine your Dark Light on it and the doorway for Room 501 will appear. Head inside and do the same again on the north east corner of the room to reveal another door out on to the balcony. Once on the balcony, head right and follow the ledge around to the gargoyle, then press X to grab the Red Gem from out of its mouth.
Gem #2 – 502 Bathroom
Leave room 501 and head down the corridor to your left, and you’ll soon find yourself in a similar situation with a noticeably-absent door for Room 502. Use your Dark Light to make the door appear again and head inside, and then perform a Suction Shot on the box blocking the doorway into the Bathroom. Head into the bathroom, vacuum up the shower curtain, and then take control of Gooigi to slip through the grate in the floor. Once in the room below, have Gooigi perform a Suction Shot on the wooden boards to break them off, revealing a valve behind them. Use his vacuum on this valve to move the needle (and therefore the flow of water), which will allow you to open the chest for a load of dosh – the gem isn’t in here though. Now, take back control of Luigi and blow air on the shower knob to turn it on, which will fill up the bath and cause a small box to fall out. Perform a Suction Shot on this box to break out the Yellow Gem.
Gem #3 – Laundry Room
Now head back across the front of the elevator and to the right and head down the small set of stairs into the seating area. Perform a Suction Shot on the vending machine to destroy it and you’ll reveal the door to the laundry room behind it. Head inside and perform a Suction Shot on the vent cover in the far left corner of the room and you’ll find the Blue Gem behind it.
Gem #4 – Hallway
Follow the corridor up (away from the screen) and around to the right, then stop in the small section between Room 505 and Room 506. You should spot the Green Gem in the teeth of a lion on the wall. Use your vacuum to suck up the ball which is on the wall a bit further towards Room 505, then fire it at the lion to smash it into pieces and free up the gem.
Gem #5 – 507 Bathroom
Run a little further down the corridor and go in to Room 507, then head through the door on the right to go into the Bathroom. Once in there, vacuum up the sheet in the top left corner of the room to reveal a secret room. Go inside, perform a Suction Shot on the case to get that out of the way, then grab the Purple Gem behind it.
Gem #6 – Room 508
Go back into the corridor and head on down to the next room, Room 508. Go inside, then go through the door in the top left corner of the room to get on to the balcony. Go up to the telescope and press X to look through it and a Ghost will appear in front of you. Defeat the Ghost and you’ll be rewarded with the Clear Gem.
And that’s it! Congratulations, you collected all six gems.