Mineral Bacon Slice

This fluorite sphalerite and galena specimen from southern Illinois was sliced with the diamond saw to see if the fluorite would be come more pronounced.  It worked fairly well.  The way the slab was cut reminds me of slices of bacon.

Fluorescent Fluorite from Rogerly Mine, England

The Rogerly Mine of England produces amazing UV fluorescent fluorite.  It is normal a green fluorite in visible light but take it outside in bright sunlight and it starts turning blue.  Longwave ultraviolet (UV) light turns this fluorite blue/purple.

UV Fluorescent Fluorite from Illinois

Most minerals that I find that fluoresce under longwave ultraviolet (UV) light tend to be white calcite.  This mineral is an exception being yellow fluorite found in southern Illinois.  One side of reacts to the light by producing a yellowish lemon colored glow.

Fluorescent Green Fluorite

Green fluorite from England that turns purple when exposed to ultraviolet light (254 nm).

Clement Museum Fluorites

Fluorite specimens seen at the Ben E. Clement Mineral Museum display at the KYANA Geological Society 2010 Show in Louisville, Kentucky.

Blue Fluorite

Blue fluorite specimen was at the Ben E. Clement Mineral Museum display at the KYANA Geological Society 2010 Show in Louisville, Kentucky.

Fluorite

Fluorite specimens that were at the Ben E. Clement Mineral Museum display at the KYANA Geological Society 2010 Show in Louisville, Kentucky.

A picture of a piece of fluorite found during a mineral dig at The Ben E. Clement Mineral Museum.  The piece in everyday light is rather plain but expose it to ultraviolet (UV) light (395 nm).  UV light makes part of the mineral glow a whitish-yellow.

Banded Fluorite

Fluorite (111.2 carats) found in Hardin County, Illinois.

Electron Microscope Image of Fluorite

Image of a fluorite crystal mined from Rosclaire, Illinois in the fluorspar district.  It is the state mineral of Illinois which was at one time the largest producer of fluorite in the United States.  The mineral is composed of calcium fluoride and its primary industrial use is in steel making (flux to remove impurities).  Fluorite is also found in Kentucky which has the Ben E. Clement mineral museum dedicated to its mining in Marion, Kentucky.

What does the surface of fluorite look like?  We need a microscope to magnify it.  Using an optical microscope at 40x magnification, one can see something like in the picture below.  Definitely there is room for improvement so one can use a scanning electron microscope (SEM) to see a much more precise view of its surface.

Luckily, a company in Delmont, Pennsylvania called ASPEX Corporation has a promotion where they will scan objects for free.  So sending them a small crystal of fluorite and a filled out form, they sent results back in about 10 weeks (it is popular and a lot of people are sending them material to scan!).

The analysis and report was done by Binyam using the PSEM eXplorer (shown in the image below) to analyze the fluorite crystal.  A manual SEM and EDX Analysis was done using Backscatter electron detection (BSED) to collect images under variable pressure conditions (0.15 Torr) and 20 KeV.

The results are shown below with 200 um and 100 um scales on the images.  This crystal surface was formed over 100 million years ago when fluorine rich water from the earth's depths made contact with calcium rich limestone closer to the surface. 

In the images shown, I assume most of the coarse surface detail is grit from mud and sand the crystal was found in.  An interesting experiment would be to clean the crystal in an ultrasonic bath in different time increments to see if this material disappeared or not.

ASPEX also scanned a fossil of 400 million year worm tube for me, see that report at this web link. See more samples of every day items at ASPEX Corporation's website.

Fluorite Crystals

These first pictures are of what appears to be a purple fluorite cube then surrounded by a second fluorite clear cube.

Fluorite From Indiana

Fluorite found in Allen County, Indiana. This specimen is on display at the Indiana State Museum.

Fluorite is calcium fluoride.

More Fluorite

Got to like the purple color of fluorite.

Fluorite

I found a pile of gravel locally and started to study the rocks within it. Here are some pieces of fluorite I picked up and photographed.

Fluorite

Fluorite specimen at the Cincinnati Museum Center meeting room display case.