Pearler

[Vania]

Australian: something impressive, extraordinary or remarkable; a prime or [unsurpassed] example of something. Similar to a [humdinger] or a [ripper].

[Luis Fok]

[Pearler] is a word that in [Australian slang] can be [taken] to mean good, or great.

[Michiko]

A beauty, a winner.
Presumably one may exclaim this when an oyster is cracked open [shucked] to reveal a pearl within its manky outter shell. In the similar fashion [eureka] was yelled when someone found gold, so that everyone in the area knew where to run towards, most likely to shoot the proclaimer, and pinch the [gold nugget].