also: こうぎょくずい
noun
carnelian
A reddish-brown variety of chalcedony used as a gemstone. Both readings refer to the same stone.
紅玉髄は古代から印章や装飾品に使われてきた。
Carnelian has been used for seals and ornaments since ancient times.
この指輪には紅玉髄がはめ込まれている。
This ring is set with a carnelian.
From 紅 (red) + 玉髄 (chalcedony). The reading べに is the native Japanese word for red, while こう is the Sino-Japanese reading of 紅.