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."

More about ambergris from Encyclopaedia Britannica.