Eudialyte is a complex silicate mineral that most commonly forms in granular patterns. It is often found in coarse grained rocks. It contains calcium, , zirconium, iron, manganese, cerium, sodium, and yttrium. It is relatively rare and also known as almandine spar. Being it rarely crystalizes it is not commonly used for gemstones. This one from the Chet Lemansky collection.
Locality: Kovdor, Kola Peninsula, Murmanskaya Oblast, Russia