Laboratory-grown is an origin
A laboratory-grown diamond has the diamond crystal structure. Synthetic is also used in gemmology for a laboratory-created material corresponding to a natural counterpart; it does not mean that the material is merely a lookalike.
An imitation is different
Moissanite and cubic zirconia can resemble diamond but are different materials. An ambiguous word such as artificial does not tell you enough. Ask for the material name and the natural or laboratory-grown origin.
Require evidence for the offered stone
Check the issuing laboratory's record and match the report details to the stone. The written quotation should state what is being sold, not rely on a broad category or advertising image. Origin and treatment disclosures belong beside the product description.
Sources and further reading
This English edition draws on the source material referenced below.