[Rockhounds] diamonds in butter

[Sicree, Andrew, Ph.D.]

I heard a story about a guy in Wisconsin? who owned
a car wash.  He got a bunch of expired butter and
coated the floor of the car wash with it.  Then he
proceeded to wash a huge amount of glacial? sand
through the car wash and found six? diamonds sticking 
in the butter.

I put the ??? in because I don't know any specific
details about this story.

Do anyone know anything about this story?  Is it
an geo-urban legend?

If it is true, can anyone give me any names, 
addresses, or other details to check on the story?

It is vaguely plausible because it is known that
diamonds will stick to grease.  (Grease table 
are/were used to catch diamonds at mines in 
South Africa.)

Thanks,

Andrew 

Andrew A. Sicree, Ph.D.