For years, the Gemological Institute of America has kept the volume of diamonds at its Gem Trade Laboratory a closely guarded secret.

However, in testimony before Congress on the “conflict diamond” issue, GIA president William E. Boyajian noted that the Institute’s “Gem Trade Laboratory grades most of the major polished diamonds that are bought and sold around the world each year, estimated at a value of some $3 billion at the wholesale level.”

That’s a sizable amount, considering that the overall diamond jewelry market amounts to around $50 billion, and the U.S. market is around $22 billion. But the actual amount of GIA-graded stones may be even greater. GIA spokesman Alex Angelle told JCK: “That is a conservative estimate, not a precise estimate, of that dollar value.”