Man-made diamonds are getting cheaper every year, which is to be expected of a product that can be produced at will. A few years ago, lab-grown diamonds sold at 30% below the Rapaport Price List which is universally used to value mined diamonds.
Today, you can pick up a GIA certified lab- grown stone for 90% below the Rapaport price. The biggest problem with man-made diamonds is the heavy energy required to grow them – albeit on a smaller scale, temperatures as hot as the sun is required. Some scientists believe growing gems requires more energy than mining them. Diamond mining implies crushing rock and sifting through rubble, and does not require the use of dangerous chemicals as in mining gold. A mined diamond is probably more eco-friendly than a man-made one. Lab-grown factories enrich a few entrepreneurs and offer no benefit to communities, such as jobs, schooling and health, as is the case with mined diamonds.
Bottom line; man-made diamonds may become the cubic zirconia of the future. If improved technology can churn them out 24/7, they will become as plentiful as cubic zirconia, which, today, cost a few dollars per carat.