chalcedonic

enUK

chal·ced·o·ny

also cal·ced·o·ny (kăl-sĕd′n-ē)n. pl. chal·ced·o·nies also cal·ced·o·nies A translucent to transparent milky or grayish quartz with distinctive microscopic crystals arranged in slender fibers in parallel bands.
[Late Latin chalcēdonius, from Greek khalkēdōn, a mystical stone (Revelation 21:19), perhaps from Khalkēdōn, Chalcedon.]
chal′ce·don′ic (kăl′sĭ-dŏn′ĭk) adj.