8 letters · 13 points in Scrabble
noun an amphibole mineral consisting of calcium magnesium silicate in monoclinic crystalline form; a source of jade that is less valuable than from jadeite; once believed to cure kidney disorders
originFrom Latin lapis nephriticus, via Ancient Greek λίθος (líthos) νεφριτικός (nephritikós), meaning kidney stone, because jade was believed to have cured kidney stones.
Etymology from Wiktionary, CC BY-SA 3.0