Ores and concentrates in Chapter 26 are materials that still require smelting or further metallurgical processing to yield a usable metal. Once the material has been smelted, refined, or otherwise processed into a metal, alloy, or intermediate product such as matte or blister copper, it falls under the appropriate metals chapter. The degree of processing and the resulting chemical composition are the key classification factors.

Cobalt ores and concentrates (2605) and certain other critical-mineral concentrates are not subject to broad US import restrictions, but their supply chains are monitored under US critical-minerals policy. Importers should be aware of potential conflict-minerals due-diligence obligations under SEC rules for certain downstream users, and should track any evolving executive actions affecting critical-mineral trade.