Lab-grown diamond
A real diamond grown in a laboratory, with the same chemical, physical and optical properties as a mined diamond.
How they are made
Two main methods are used. HPHT, high pressure high temperature, recreates the conditions deep in the earth. CVD, chemical vapour deposition, builds the crystal layer by layer from a carbon-rich gas. Both produce diamond, not an imitation.
Grading and disclosure
Lab-grown diamonds are graded for cut, colour, clarity and carat like mined diamonds, and major labs issue reports for them. Many reports and laser inscriptions identify the stone as laboratory grown. Sellers must disclose it clearly, and many markets require wording such as lab-grown or laboratory created.
Lab-grown versus simulants
Moissanite and cubic zirconia are different materials that imitate diamond. A lab-grown diamond is diamond, so it is not a simulant.
Rendering lab-grown diamonds
Because the optical properties are the same, render a lab-grown diamond exactly like a mined one, with an IOR of about 2.42 and a dispersion of about 0.044. Any visible difference in real life comes from the cut, colour and clarity of the individual stone, not from its origin.
If your listing offers both natural and lab-grown options, the same images can serve both when the cut and size match, but state clearly in the text which version the buyer is choosing.