Columbium (element)
鎶 is a rare kanji used for the chemical element columbium (niobium). Its meaning is strictly that element, with no broader conceptual center.
鎶 is a modern coined character for the element columbium, combining the metal radical 金 with 哥 for its sound value カ.
The metal radical 金 on the left marks it as a metallic element, and the right side 哥 suggests the reading. Picture a shiny piece of columbium stamped with the character 哥.
For カ, imagine a car made of columbium: car -> カ, and the metal gleams like the element.