Crown (King Boo)

King Boo's Crown is the final piece of jewelry Luigi collects before he saves Mario in Luigi's Mansion. In Luigi's Mansion, the crown holds a red diamond at the top. Officially, King Boo's crown also counts as a Red Diamond. The crown is worth the same amount as a single coin.

The crown has changed in the later Mario games it has appeared in. It is nowadays shown as a golden crown encrusted with jewels, similar to Princess Peach's crown.

In Luigi's Mansion: Dark Moon, however, King Boo appears to sport the crown's initial appearance, except the gem, which is now a stone that resembles an amethyst, matching King Boo's color theme. This gem gives him enough power to shatter the Dark Moon.

Trivia

 * King Boo's Crown is the only unit of money in the game that must be collected, so, albeit hard, it is possible to only get 5,000 G.
 * King Boo's Crown from Luigi's Mansion: Dark Moon bears a striking similarity to a purple Chaos Emerald.