jade ornament semicircular in shape
璜 refers specifically to a semicircular jade ornament, a type of ceremonial or decorative piece made of jade.
璜 combines 王 (jade) with 黄, which likely contributes the sound. The character specifically denotes a semicircular jade ornament.
The left side 王 (jade) and the right side 黄 (yellow) together suggest a yellow jade piece. Picture a semicircular yellow jade ornament worn as a pendant.
For コウ, imagine a semicircular jade ornament glowing with a warm, golden hue: the glow cues コウ, and the jade piece is the ornament.