2830.90.10.00 - Zinc sulfide, luminescent grade having a purity of 99.99 percent or more by weight

This HTS category specifically classifies luminescent-grade zinc sulfide characterized by an exceptionally high purity of 99.99 percent or more by weight. This precise chemical composition is critical for its intended application in luminescence, where even minute impurities can significantly affect light emission properties. Such high-purity zinc sulfide is typically used in specialized applications like phosphors for display technologies, cathode ray tubes, and other optical devices requiring precise light output and color rendering.

Distinguishing this category from its siblings, 2830.90.15.00 "Other zinc sulfide" covers zinc sulfide that does not meet the stringent 99.99% purity requirement or is not specified as luminescent grade. Cadmium sulfide (2830.90.20.00) is classified separately due to its distinct chemical makeup and properties. The broader "Other" category (2830.90.90.00) encompasses all other sulfides and polysulfides not specifically listed in preceding subheadings.

As this is a leaf node within the HTS structure, there are no further subcategories. Therefore, classification under 2830.90.10.00 hinges entirely on meeting the specified purity and grade criteria. Importers and exporters must ensure that documentation accurately reflects the material's purity and intended luminescent use to correctly classify these high-purity zinc sulfide products.