This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
鑮 combines 金 (metal) with 薄, which likely contributes the sound. The exact historical development is uncertain.
The left side is metal 金, and the right side is 薄 (thin). Picture a thin metal object, but its exact purpose is unclear.
For ハク, imagine a thin metal sheet that makes a 'haku' sound when struck: haku -> ハク.