However, in recent years it has become possible to produce gem-quality synthetic diamonds of significant size.

But gem-quality manufactured diamonds remain only an unfulfilled promise.

Sierra Leone is a major producer of gem-quality diamonds.

We've run it through the usual tests," the doctor said, "and it's unquestionably carved from a gem-quality diamond.

Until now, Argyle's gem-quality diamonds have been sold in private tender offerings.

Only about 1 in 200 kimberlite pipes contain gem-quality diamonds.

Rich alluvial diamond deposits make Namibia a primary source for gem-quality diamonds.

Gemesis is the principal producer of gem-quality lab-created diamonds and jewelry.

But during that period, the market for gem-quality diamonds was flat.

Angola's mines produce some of the finest gem-quality alluvial diamonds in the world.