Pearl

Pearls are collectible items dropped by non-area boss Portrait Ghosts in Luigi's Mansion. They determine which frame the Portrait Ghost has and the portait photo after being returned to the Gallery.

Pearls are absent from the Boss Rush mode of the Nintendo 3DS remake, but Luigi can still achieve higher frames based on how well he fights a Portrait Ghost.

Luigi's Mansion
In Luigi's Mansion, there are three sizes of pearls: small, medium, and large. The smaller ones are awarded for every 10 HP that Luigi vacuums from the Portrait Ghost, up until reaching 50 HP, which is when it begins to drop medium-sized pearls per 10 HP vacuumed. The cycle reverts to small pearls if Luigi unsuccessfully captures the Portrait Ghost on the first turn, unless he can vacuum another 50 HP from it. This is unlikely because Portrait Ghosts have 100 HP, meaning it must break free from Luigi precisely halfway (with 50 HP remaining).

A small pearl is worth 50,000G, which is half of a Gold Bar's value. A medium pearl is worth 100,000G, and a large pearl is worth 1,000,000G. If Luigi successfully captures a Portrait Ghost on the first try, it drops four small pearls, four medium pearls, and one big pearl, totaling to 1,600,000G in value.

The only non-boss Portrait Ghosts to not drop pearls are paired with another ghost. The blue Clockwork Soldier drops pearls, therefore the pink and green ones do not. Between Henry and Orville, the latter one drops the pearls. The Floating Whirlindas are simultaneously vacuumed, meaning that they share dropped pearls.

After completing an area, Luigi releases the captured Portrait Ghosts into the Ghost Portrificationizer. Their frame and photograph are based on which pearls were collected by Luigi. The frame turns brown if Luigi only collects small pearls, silver for both small and medium ones, and gold if he collects every pearl of each size.

Luigi can earn up to 76 small pearls, 76 medium pearls, and 19 big pearls in the entire mansion if he manages to successfully vacuum up every Portrait Ghost in one turn. These pearls all add up to 30,400,000G in total. Luigi can earn up to 171 small pearls if he does not collect medium or large pearls. Like the other collected items, Luigi can check the pearls he has collected from the Game Boy Horror.

Luigi's Mansion 3
Pearls reappear as collectible items in Luigi's Mansion 3, where they are the rarest and most valuable collectible. Unlike in Luigi's Mansion, the Pearls are worth 100G.

Luigi's Mansion (Nintendo 3DS)

 * Digital manual description: "These are dropped by portrait ghosts. They come in small, medium, and large sizes, and earning them will improve the frames and portraits in the gallery."