Any of a group of minerals related to apatite, containing rare-earth elements (especially cerium) and typically occurring as pale yellow to dark brown or black masses of prismatic crystals. Now frequently with a suffix indicating the predominant rare-earth element.
The earliest identified of these minerals is britholite-(Ce), a silicate and phosphate of cerium and calcium, (Ce, Ca)₅(SiO₄, PO₄)₃(OH, F). Crystal system: hexagonal.
Late 19th century. From ancient Greek βρῖθος weight (from βρίθειν to be heavy, of uncertain origin, perhaps ultimately from the same Indo-European base as Early Irish bríg strength, power) + -o- + -lite.