Gem

Gemstones are valuable objects found in Luigi's Mansion: Dark Moon. There are thirteen Gemstones hidden in each of the five mansions in the game, making a grand total of sixty five Gemstones in the entire game. Amethysts are found in Gloomy Manor, emeralds are found in Haunted Towers, rubies are found in Old Clockworks, sapphires are found in Secret Mine, and diamonds are found in Treacherous Mansion. The coloration of the five sets of thirteen Gemstones corresponds to the theme of the five mansions. Unlike the Red, Silver, and Gold Diamonds found in the original game, Gemstones do not function as a form of currency, but rather as a collectible. Once the player has collected all thirteen Gemstones in a mansion, they will be rewarded with one of five different statues of Luigi with the Gemstones encrusted in the stand. The player can see the Gemstones they've collected inside the Vault, on the mansion select screen, when one is collected in a mansion, and when the totals and records are displayed at the end of a mission. Any statues that have been unlocked can only be viewed inside the Vault.

Some Gemstones can be obtained in any mission, while some can only be obtained in a specific mission or once certain conditions have been met.

Amethysts
{| class="wikitable" !Image !Gem !Available Missions !Location
 * Round Amethyst
 * A-1, A-2, A-3, A-4, A-5, A-Bonus
 * Mudroom Exterior - In the Mudroom, the player should use their Strobulb on the right door to open it. When they are outside they'll need to vacuum this gem down from the trees at the end of the path.
 * Trillion Amethyst
 * A-1, A-2, A-3, A-4, A-5, A-Bonus
 * Front Yard - Use the Strobulb on the flowers.
 * Baguette Amethyst
 * A-2, A-3, A-4, A-5, A-Bonus
 * Parlor - Use the Strobulb on the clock.
 * Football Amethyst
 * A-2, A-3, A-4, A-5, A-Bonus
 * Studio - The player should look into the camera to notice the gem hidden behind the left-most curtains.
 * Drop Amethyst
 * A-3, A-Bonus
 * Entrance - The player should press X near the right suit of armor to knock down its helmet. The player can then use the helmet to hit a painting on the left wall.
 * Pebble Amethyst
 * A-3, A-4, A-5, A-Bonus
 * Dining Room - The player needs to use the Strobulb on a safe in the ceiling.
 * Rhombus Amethyst
 * A-3, A-4, A-5, A-Bonus
 * Kitchen - The player should interact with the stove (walk up to it and press X) in order to start up a fire. Then, the player should open the fridge to reveal this gem frozen in ice. The player can melt the ice using the stove's open flames.
 * Star Amethyst
 * A-3, A-4, A-5, A-Bonus
 * Foyer - In the Common Hall, the player should go to the end of the hall and use the Dark Light to reveal a hidden door. The door will lead to the Patio. In the Patio, the player can reveal another door along the left wall using the Dark Light. The player should enter the door to be in a new area (Under the Stairs). The player should then take the door on the left to be taken to the Foyer (behind the fish tank), where the Amethyst can be found.
 * Octagon Amethyst
 * A-3, A-4, A-5, A-Bonus
 * Patio - The player should use the Dark Light to reveal a hidden fountain next to the other two in the water.
 * Oval Amethyst
 * A-3, A-4, A-5, A-Bonus
 * Library - The player should use the Dark Light to reveal a hidden globe along the left wall. The player can then shoot the globe out of the Poltergust 5000 to reveal the gem.
 * Spindle Amethyst
 * A-2, A-3, A-4, A-5, A-Bonus
 * Study - The player needs to pull down the left-most curtains on the back wall. Then the player will need to shine the Dark Light on the painting to reveal the gem.
 * Coffin Amethyst
 * A-5, A-Bonus
 * Rafters - This gem is on top of a dresser on the far-right side of the area. The player can vacuum it down easily.
 * Mushroom Amethyst
 * A-5, A-Bonus
 * Bedroom - Burn the giant web, then run behind it to find this Amethyst.
 * Once You Collect All Amethysts You Get A Scared Luigi Statue
 * Octagon Amethyst
 * A-3, A-4, A-5, A-Bonus
 * Patio - The player should use the Dark Light to reveal a hidden fountain next to the other two in the water.
 * Oval Amethyst
 * A-3, A-4, A-5, A-Bonus
 * Library - The player should use the Dark Light to reveal a hidden globe along the left wall. The player can then shoot the globe out of the Poltergust 5000 to reveal the gem.
 * Spindle Amethyst
 * A-2, A-3, A-4, A-5, A-Bonus
 * Study - The player needs to pull down the left-most curtains on the back wall. Then the player will need to shine the Dark Light on the painting to reveal the gem.
 * Coffin Amethyst
 * A-5, A-Bonus
 * Rafters - This gem is on top of a dresser on the far-right side of the area. The player can vacuum it down easily.
 * Mushroom Amethyst
 * A-5, A-Bonus
 * Bedroom - Burn the giant web, then run behind it to find this Amethyst.
 * Once You Collect All Amethysts You Get A Scared Luigi Statue
 * Coffin Amethyst
 * A-5, A-Bonus
 * Rafters - This gem is on top of a dresser on the far-right side of the area. The player can vacuum it down easily.
 * Mushroom Amethyst
 * A-5, A-Bonus
 * Bedroom - Burn the giant web, then run behind it to find this Amethyst.
 * Once You Collect All Amethysts You Get A Scared Luigi Statue
 * Bedroom - Burn the giant web, then run behind it to find this Amethyst.
 * Once You Collect All Amethysts You Get A Scared Luigi Statue