kind of jade
珦 refers to a specific kind of jade, a precious ornamental stone. The meaning is narrow and concrete, without broader abstract extensions.
珦 combines 王 (jade) with 向, which likely contributes the sound. The exact historical development is uncertain, but the structure suggests a phono-semantic compound for a type of jade.
The left side 王 (jade) tells you it's a precious stone. The right side 向 looks like a face turned toward something. Imagine a rare jade that always faces the light, showing its unique color.
For キョウ, picture a jade stone in the shape of a key: key -> キョウ. The jade key unlocks a treasure box.