After a little searching on hte internet I found some references to
Swiss Diamonds. This is a term used to describe diampods that have
been routed through Switzerland (most notably to “cleanse” them) and
includes “blood Diamonds”.
A quote from one report:
It also questioned an assertion by DeBeers, the South African
diamond mining giant, that only 4 percent of the world's gems
were illicit or "blood" diamonds as well as claims by India,
Israel, Belgium and other trading centers that gems from
conflict areas did not reach them "directly.
For example, many diamonds to Britain pass through Switzerland,
which has no mines, and therefore are called “Swiss” diamonds.
Conversely, diamonds from Britain going to Israel are also
transferred through Switzerland and again called “Swiss” diamonds,
the report said. And another report said (in part):
These diamonds are stored in vaults on Swiss soil but for
statistical and tax purposes they are not in Switzerland.
Air cargo papers for the stones, however, mention Switzerland and
create a class of “Swiss” diamonds.
“The diamonds can stay here for ever and the client does not have to
pay any tax anywhere. We don’t know where they come from and where
they will go to. We get them, store them, and release them,” said
the employee, who requested anonymity.
At Zurich airport alone, some 70 transport firms use tax-free
storage for precious stones and metals. He said Swiss customs rules
were perhaps more lenient than other countries’.