Boron & Tellurium

The Harmonized System groups them under heading 2804 as nonmetallic elements, and the US schedule separates them at the 10-digit level (2804500010 for boron, 2804500020 for tellurium). Despite their different end-uses, both are traded as refined elemental materials and share the same chapter-level classification logic.

Tellurium is a primary material in cadmium telluride photovoltaic panels and is listed as a critical mineral by the US government. Its supply is largely a byproduct of copper refining, making availability sensitive to copper production cycles and concentrated among a limited number of global refiners.