Lab-grown and reconstructed gemstones — including synthetic rubies, sapphires, emeralds, and cubic zirconia — in their unworked, sawn, or roughly shaped state are classified here, explicitly excluding piezo-electric quartz which has its own heading. The chemical and physical identity of synthetic stones with their natural counterparts does not change the classification, but it is central to valuation: synthetic stones carry substantially lower dutiable values than natural equivalents, and misrepresentation of a synthetic stone as natural is a significant customs fraud risk. FTC disclosure rules require that 'synthetic,' 'lab-created,' or 'lab-grown' qualifiers accompany any trade description of these materials. Importers should ensure invoices clearly identify the manufacturing method (Verneuil, Czochralski, hydrothermal, flux, or CVD) to support both classification and downstream disclosure obligations.

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