Atomic Positional Parameters
Ca 4a 0.0000 0.0000 0.0000
F  8c 0.2500 0.2500 0.2500

Reference
AK Cheetham, BEF Fender and MJ Cooper (1952) Journal of Physics C, 4, 3107

Mineral Chemistry
In fluorite, calcium ions are coordinated to eight fluoride ions, and each fluoride is tetrahedrally coordinated to four calciums. Fluorite may occur throughout the whole range of mineralizing fluid temperatures, from as high as 450 - 550^oC as a hydrothermal product of granite intrusions, to low temperature deposition as a cement in sandstones.

In hydrothermal vein deposits, fluorite may be associated with barite, sphalerite, galena, calcite and quartz. Minerals which crystallise with the fluorite structure include uraninite, cerianite, and thorianite. Partial substitution of yttrium and cerium for calcium in fluorite gives yttrofluorite.


The CHIME figure shows calciums as grey spheres coordinated by eight fluoride ions - shown as ochre spheres. The unit cell is outlined.