10 letters · 21 points in Scrabble
noun a milky or greyish translucent to transparent quartz
originBorrowed from Latin chalcēdōnius, from Ancient Greek χαλκηδόνιος (khalkēdónios), from Ancient Greek χαλκηδών (khalkēdṓn), cognate to Arabic كَرْكَنْد (karkand).
Etymology from Wiktionary, CC BY-SA 3.0