Zirconium with a hafnium-to-zirconium weight ratio of 1:500 or less is nuclear-grade material suitable for reactor fuel cladding, because hafnium's high neutron-absorption cross-section would degrade reactor performance at higher concentrations. The US tariff schedule maintains separate subheadings for this low-hafnium grade (810921, 810931, 810991) versus standard commercial-grade zirconium, and the distinction also triggers Nuclear Regulatory Commission licensing considerations for certain forms.

Zirconium used in ceramic and refractory applications is typically supplied as zirconium oxide (zirconia) or zirconium silicate, which are classified in the chemicals or minerals chapters rather than here. Heading 8109 covers the metal itself and articles thereof. Importers of zirconium-based ceramic materials should verify whether their product is the metal, an oxide, or a mineral compound before applying this heading.