Bastnäsite

Bastnäsite is the name of a mineral group belonging to the carbonates and nitrates class.
Bastnäsite contains rare earth metals like Cer, Lanthan, Neodym, Praseodym, Samarium, Gadolinium, Europium, Yttrium and several others.

By far most common is Bastnäsite-(Ce)

Bastnäsite shop
 


Fine Bastnäsite from Pakistan

Origin of name: Bastnäsite was first found in 1838 in an ore mine near Bastnäs in the vicinity of Skinnskatteberg, Västmanland Province, Sweden. in 1841 French mineralogist Jean Jacques Nicolas Huot described the new mineral and named it after its type locality.
Quelle: Wikipedia

Synonyms and trade names: Bastnaesite

Can be confused with: a wide range of similarly coloured gems like tourmaline, zircon, chrysoberyl, some garnets and quartzes, andalusite and more

Localities: to date more than 500 deposits are known on all continents except Antarctica. Commercially most important sources are China, California and Madagascar. However, transparent gem quality Bastnäsite is very rare, indeed and mostly found in France (Luzenac) and Pakistan (Zegi Mountain).

Handling: Bastnäsite is soft, quite brittle, highly sensitive to acids and thus hardly suitable for jewellery

Worth knowing: Bastnäsites are the most important source for so-called Lanthanoides, a group of rare earth metals used for a plethora of products like computer hard drives, flat screen monitors, cell phones, loudspeakers, batteries, catalytic converters, energy-saving lamps and coatings of welding goggles, to name just a few.
Ceroxide is used for polishing precision lenses for microscopes and cameras as well as gem stones.

Bastnäsite shop

Gemmological Properties of Bastnäsite

Formula:
(Ce/Nd/Y/REE)(CO3)F (REE=rare earth element)
Crystal system:
hexagonal
Mohs hardness:
4 - 4.5
Specific gravity:
4.8 - 5.2
Refractive index:
doubly refractive
Max. Birefringence:
1.72 - 1.82
Dispersion:
0.10
Pleochroism:
none
Luminiscence:
weak
Lustre:
vitreous to waxy
Cleavage:
indistinct
Fracture:
uneven, brittle
Colour:
yellow, brownish red to dark brown