System: monoclinic Hardness:5-5½ Rarity:not common
Strunz id:VII/B.1-10 -
PHOSPHATES, ARSENATES and VANADATES
Name origin: Named "hydro-herderite" in 1894 by Samuel L. Penfield. Named changed to "hydroxyl-herderite" by Palache, Berman, and Frondel in 1954. Originally named for Siegmund August Wolfgang von Herder (1776-1838), Mining official in Freiberg, Germany. The "Hydroxyl-" prefix signifies the dominance of hydroxide over fluorine.