gem
璅 centers on a precious stone or jewel: a gem.
璅 combines 王 (jade/gem) with 巢, which likely contributes the sound. The exact historical development of the right component is uncertain.
The left side 王 (jade) tells you it's a precious stone. The right side 巢 looks like a nest, but here imagine a gem hidden inside a bird's nest.
For ソウ, picture a gem so bright it makes you say 'so!' in surprise: so -> ソウ, and the gem sparkles in its nest.
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