Fire method: burn the gemstone with a lighter, moissanite will appear slightly yellow, but after annealing, it will return to its original state, while the color of lab grown diamond will not change after the fire. But be careful, do not exceed 600 degrees, or the real lab grown diamond will oxidize. Unless as a last resort, generally do not try this method to avoid disputes.
However, it was not until 1970 that gem-quality diamonds with large grains were synthesized by the American company General Electric. After nearly thirty years of effort, it is now possible to obtain crystals as large as a dozen carats, but the cost of gem-quality diamond synthesis is still too high to allow for mass production. only 3,500ct of synthetic diamonds could be cut and ground in 2000, representing only 0.01% of natural gem-quality diamond production that year.