Synthetic Precious & Semiprecious Stones, Worked but Not Mounted or Set (Other Than Diamonds)

Cubic zirconia is a synthetic material used as a diamond simulant and is generally classified as a synthetic precious or semiprecious stone under heading 7104. Worked, unset cubic zirconia would typically fall under 7104991000 (if cut for jewelry) or 7104995000. Moissanite (synthetic silicon carbide used as a gem simulant) may be classified similarly, but its precise classification can depend on CBP's determination of whether it constitutes a 'precious or semiprecious stone' — a licensed customs broker should confirm the applicable line.

For customs purposes, the country of origin of a worked gemstone is generally the country where the last substantial transformation occurred — typically the country where the stone was cut and polished, not where the rough was grown. This means a synthetic sapphire boule grown in one country but cut in India would ordinarily be declared as Indian origin, which has implications for any applicable trade-remedy measures.