Lab-grown diamonds are, from a chemical perspective, as much real diamonds as natural diamonds. Carbon atoms in a Diamond Cubic crystallographic structure. It's quite common these days and affordable to make them in the lab. The natural diamond industry is pretty dirty, with prices artificially controlled by the De Beers company. Diamonds should not cost as much as they do.

Remember in gangster movies how when a police undercover infiltrated a gang and he played the role of a diamond dealer. It was based on truth, the gov could make diamonds for cheap, having unlimited supply. The gangsters had no idea at the time. The cost of materials for diamonds is nothing, just carbon.