Parisite-(Ce)

Parisite is a rare mineral consisting of cerium, lanthanum and calcium fluoro-carbonate, Ca(Ce,La)₂(CO₃)₃F₂. Parisite is mostly parisite-(Ce), but when neodymium is present in the structure the mineral becomes parisite-(Nd).

It is found only as crystals, which belong to the trigonal or monoclinic pseudo-hexagonal system and usually have the form of acute double pyramids terminated by the basal planes; the faces of the hexagonal pyramids are striated horizontally, and parallel to the basal plane there is a perfect cleavage. The crystals are hair-brown in color and are translucent. The hardness is 4.5 and the specific gravity is 4.36. Light which has traversed a crystal of parisite exhibits a characteristic absorption spectrum.