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.

Britholite-(Ce)
A photo of the mineral
General
Category	Minerals
Formula	(Ce,Ca)5(SiO4)3OH
IMA symbol	Bri-Ce[1]
Crystal system	Hexagonal - Dipyramidal
Space group	P63/m
Identification
Colour	Brown, greenish brown, yellow, resin brown, black
Mohs scale hardness	5.5
Luster	Adamantine - Resinous
Specific gravity	4.45
Density	4.45
Major varieties
hardness	5.5 on the Mohs scale
type locality	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.^[2]