Fluorite is Calcium Fluoride, it can come from every continent and has an amazingly broad array of colors and shapes. Entire collections are composed of various Fluorite from various locales.
Fluorite is in the Hexoctahedral class and can form in any variant of that form from Cubes to Hexoctahedrals and with modifications.
Factors to look for: Color, Form, Luster, Phantoms, Crystalographic Modifications, Associations, Less or No Damage, Unusual Forms or Dissolution Modifications.
Illinois is the most famous U.S. Locale for Fluorite and is known for having the widest variety of high quality specimens with the most diverse associations in the United States.
Southern Illinois has some of the most aesthetically and geologically diverse Fluorite specimens in the entire world and certainly in the U.S. featuring hundreds of variations in color, associations, shape, and, size. Pieces of true quality will always be difficult to locate but we try to provide a large assortment at NSC at all times.
There were over a hundred mining locations in southern Illinois which were largely mined for ores until the mid 90s when most of the locales shut down due to impracticality of production and costs. Since then Fluorite from these locales have steadily increased in value and will continue to do so as more of the finer specimens are sequestered into private collections or are damaged from mishandling. These have seen one of the largest value changes in mineralogical history when observed from the 1960s price points to now and are still solid investments for the mineral collector.
Newly discovered from New Mexico, this material is from a locale called the "Surprise Mine" which is located in Luna County. The geology appears to be a largely limestone replaced vein structure that has many magenta color fluorite with green phantoms. Sometimes they also have a generation of blue cubic fluorite and occasionally the green layer shows as an isolated generation which can be octahedral or dodechahedral.
Luna County has produced somewhat similar material in the past, however, nothing quite like this and nothing to this quality. This location is dug by only two men and the production so far hasn't been huge but the specimens that have come out have been quality and interesting pieces.