No. Heading 2507 explicitly covers kaolinic clays whether or not calcined, so both raw and calcined (including metakaolin) forms remain under this heading. The calcination step changes the physical and chemical properties — and the commercial grade — but does not move the product to a different heading.

Kaolinic clays are defined by their predominant kaolinite mineral content. Clays that do not meet the kaolinite-dominant criterion — such as bentonite, ball clay, fire clay, or fuller's earth — fall under the adjacent heading covering other clays. When a clay's mineralogy is ambiguous, laboratory analysis of the mineral composition is the standard method for resolving the classification.