7104.91 - Diamonds:

This HTS category, 7104.91, specifically covers diamonds that are classified under the broader heading of "Synthetic or reconstructed precious or semiprecious stones, whether or not worked or graded but not strung, mounted or set; ungraded synthetic or reconstructed precious or semiprecious stones, temporarily strung for convenience of transport." Within this heading, 7104.91 focuses on "Other" diamonds that do not fit into more specific sub-classifications. This implies that while these are diamonds, they are not natural diamonds or are diamonds that have undergone some processing or treatment that places them outside the natural diamond classifications.

The distinction between 7104.91 and its sibling category, 7104.99, lies in the material. While 7104.99 covers "Other" synthetic or reconstructed precious or semiprecious stones, 7104.91 is exclusively reserved for diamonds within this synthetic or reconstructed framework. Therefore, if an item is a diamond and falls under the scope of synthetic or reconstructed stones, it will be classified under 7104.91, rather than a broader category for other types of synthetic or reconstructed gemstones.

This category, 7104.91, is further subdivided to provide more granular classification for diamonds that are not natural. The subcategories, 7104.91.10.00 and 7104.91.50.00, distinguish between diamonds that are cut but not set and are suitable for jewelry manufacturing, and all other diamonds that fall within this synthetic or reconstructed classification. This allows for specific tariff treatment based on the readiness for incorporation into finished goods, such as jewelry, or other forms of presentation.