Britholite-(Ce)

Britholite-(Ce) is a rare radioactive mineral with the chemical formula (Ce,Ca)5(SiO4)3OH. It comes in a variety of different colors. Its type locality is Naujakasik (Naajakasik), Tunulliarfik Fjord, Ilímaussaq complex, Narsaq, Kujalleq, Greenland.

Discovery
The mineral was first discovered by Gustaf Flink in 1897 inside a nepheline-syenite at Naujakasik, Ilímaussaq complex, Greenland. It was named after the Greek word βρῖθος (brithos) which means "weight" referring to its high specific gravity, it was later named britholite-(Ce) due to the high amounts of cerium in its composition.