piece of precious jade
璠 centers on a specific type of precious jade, referring to a fine ornamental piece or gemstone.
璠 combines the jade radical 王 with 番, which likely contributes a phonetic element. The character is used specifically for a type of fine jade.
The jade radical 王 on the left marks it as a gemstone, while 番 on the right can be thought of as a numbered piece in a collection. Imagine a numbered display case holding a single precious piece of jade.
For ハン, picture a hand holding a piece of precious jade: hand -> ハン, and the jade is so fine it fits in one hand.