jewel
珸 centers on a jewel or gem, specifically a type of precious stone. The meaning is narrow and concrete, without abstract extensions.
珸 combines the jewel radical 王 (玉) with 吾, which likely contributes the sound. The exact historical development is uncertain, but the structure suggests a phono-semantic compound for a type of gem.
The left side is the jewel radical 王 (a string of jade beads), and the right side is 吾 (a mouth 口 over five 五). Imagine a precious jewel being described by a mouth saying 'five'—perhaps a five-carat gem.
For ゴ, picture a jewel that glows with a golden 'go' light: go -> ゴ, and the gem shines.