milky white stones

?if [Osama] bin Laden?s currency-to-diamonds conversion scheme worked?and the indication is that it did, for Al Qaeda operatives seem to have begun three years before the [9/11] attacks?the network kept up to several million dollars worth of assets in the form of milky white stones, the most compact form of wealth known to man.?

?Greg Campbell, from Blood Diamonds: Tracing the Deadly Path of the World?s Most Precious Stones, 2002.