In the “Bring the Diamonds to the Necklace” mode, a certain number of Diamonds need to be brought to the area where the Necklace is located.
You do this by clearing the Charms between the Diamond and the Necklace until they are reunited.
The diamond needs to be brought to the necklace. Like the Charms, it is affected by physics.
Usually, there are several of them inside a single level.
The location of the Necklace, usually at the bottom of the screen, is the place where the Diamonds need to be brought.