Both characters carry the
玉 (jade) radical, marking
玛瑙 as a precious stone. Xinhua notes the name comes from the swirling pattern resembling a horse's brain (
马脑 mǎ nǎo) — the
王 (jade) radical was added to make
玛瑙. It is one of the seven Buddhist treasures (
七宝) and prized in Tibetan and Mongolian jewelry.
