HÃÂ¥leniusite-(La), chemical formula . is a yellow isometric mineral. It has a dull, earthy lustre. The geological setting of hÃÂ¥leniusite-(La) is in vugs and leaching zones of massive ferriallanite-(Ce), intimately intergrown with cerite-(Ce) and bastnäsite-(La).
It was discovered in 1986 at Bastnäs mines, Riddarhyttan, Skinnskatteberg, Västmanland, Sweden and named in honour of Ulf HÃÂ¥lenius, director of the mineralogy department at the Swedish Museum of Natural History in Stockholm, Sweden.