Luigi’s Mansion 3’s sixth floor — 6F : Castle MacFrights — has six hidden gems. In this guide, we’ll show you their map locations and how to find them all throughout the level.
On every floor, gems appear in the same order from left to right in the menu: clear, red, blue, green, purple, and finally yellow. We’ll follow the same order below.
6F COLISEUM BALCONY [CLEAR GEM]
After you defeat the boss, you’ll take the stairs up to the coliseum balcony. The sixth floor’s white gem is sitting in from of a suit of armor, right in the middle of your path out.
6F HALL OF ARMOR [RED GEM]
Shine your Dark-Light (hold X) at the space in the upper right corner of the room where there should be a set of armor. Suck up the orbs that appear, and you’ll claim the sixth floor’s red gem.
6F CELLAR [BLUE GEM]
There are three gigantic barrels along the top wall of the cellar. Destroy (with a ghost, or use your plunger) the front of the rightmost barrel. Walk inside, and then walk to the right into a secret passage that you can’t see. Climb up the ladder (that you also can’t see unless you looked through the crack in the wall), and collect the sixth floor’s blue gem at the top.
6F ROYAL COFFERS [GREEN GEM]
About three-quarters of the way through the Coliseum Hallway, vacuum up (down?) a tapestry, and shine your Dark-Light (hold X) at the suspiciously door-shaped indentation of stone behind it. Suck up the orbs that appear, and the door to the Royal Coffers room will materialize. Enter, get an achievement, collect a ton of money, and grab the sixth floor’s green gem.
6F ARMORY [PURPLE GEM]
Look for the loose bricks in the wall at the top of the room. Use your plunger to pull them, lift the wall, and claim the sixth floor’s purple gem from a huge hidden chest.
6F CAGE-LIFT ROOM [YELLOW GEM]
Use the windmill-like device to descend to the lower floor of the vertical room. At the bottom level, have Luigi blow on the windmill-like device near the door along the left wall. (It’s difficult to see, but it’s between the torch on the elevator and the locked door.) That’ll lower the hanging cage holding the gem. Walk Gooigi into the cage to collect the sixth floor’s yellow gem.