Gagarinite-(Ce)

Zajacite or Zajacite-(Ce) is a rare radioactive fluoride mineral with formula: Na(REE_xCa_1-x)(REE_yCa_1-y)F₆. REE means rare earth elements mostly those belonging to the lanthanide series. It crystallizes in the trigonal - rhombohedral system It has a white vitreous appearance with a conchoidal fracture. It has a Mohs hardness of 3.5 and a specific gravity of 4.44 to 4.55. It is transparent with refractive indices of nω=1.483 and nε=1.503. It occurs as creamy to white grains and phenocrysts in pegmatite and aplite pods or lenses in a peralkaline igneous intrusion.

It was discovered in 1993 at Strange Lake, Quebec - Labrador (56°20'N , 64°10'W) and was named for Dr I. S. Zajac who lead the expedition responsible for its discovery.

See also

• List of minerals
• List of minerals named after people

References

• Webmineral data
• Mindat w/ location data