Ambergris

When:

Lookups spiked on January 31, 2013.

Why:

A British man found an unusual rock that turned out to be ambergris.

Or as a headline in the Mirror explained,

Dog walker finds smelly lump of whale vomit on beach that's worth £100,000

Ambergris is "a waxy substance from the sperm whale that is used to make perfumes."

The word derives from the French words meaning "gray amber."