On average, slightly better.
are optically, chemically, physically and thermally the same as mined.
Over the past few years, experienced producers are able to turn out diamonds that are mostly in the D-G color range, and VS+ clarity. That is MUCH higher than the run-of-mine (a random sample) in a conventional mining operation.
There is also talk that there may be a need to introduce a new color grade — D+, or even C — to reflect the higher level of colorlessness that’s now achievable in a lab.
TO CLARIFY: A G/VS lab-grown is the same as a G/VS mined. The point is that high color and clarity goods are more common in a lab than in the ground.
And the lab-growns are currently 1/3 the price of mined.