Identify It! Answer for 11-20-2009

Thank you everyone who guessed in this week’s “Identify It!” challenge. Sorry that its taken us longer to get our answer posted than usual but its been a busy week getting ready for Thanksgiving. We’ve done three of these challenges so far and I’m always interested in people’s responses and their thought process.

We had some really good guesses this week but amazingly I was able to stump the fans because no one guessed the correct answer. I was actually expecting this one to be guessed very quickly but I guess we don’t have very many hardcore geologists or mineralogists in the audience at the moment.

Here is the answer: The object in question is a 6 inch diameter by 4 inch tall crystal formation of the mineral Fluorite. This formation is partially transparent (around some corners of some crystals) but is mostly translucent having a purple to violet color. It exhibits a cubic crystal formation typical of fluorite. More images (showing translucency and better coloration) can be found at our fan page on Facebook under the photo’s tab inside the “Rocks and Minerals” folder.

(see: )

Another View of our Fluorite Crystal

Another View of our Fluorite Crystal

Fluorite is a widely occuring mineral that is often found in large deposits. It is a halide made of calcium fluoride (CaF2) and is found most often as cubic crystals though octahedral and more complex forms are possible. Fluorite occurs in a wide variety of colors including colorless, yellow, green, blue, purple and more rarely black, brown, red, pink, and white. Some fluorite samples fluoresce under ultra-violet light (fluorescence is actually named after fluorite, one of the first minerals discovered to posses this trait)

Fluorite uses include: ornamental use, as a gemstone, as a flux in steel and aluminum production, as a substitute for glass in some high quality optics applications, in some semiconductor manufacturing processes involving ultraviolet light, and in the production of hydrofluoric acid.

You can learn more about Fluorite and find pictures of very interesting samples at the following links:

A data table containing lots of information about Fluorite:

Pictures of museum samples of Flurite:

Bob’s Fluorite Gallery:

Lots of information and pictures of Fluorite:

Wikipedia Entry on Fluorite:

(standard disclaimer: Wikipedia is not a primary source and since the site is publicly editable by anyone the accuracy of information should be called into question. Nevertheless Wikipedia is an interesting experiment as a publicly edited and maintained information repository similar to an encyclopedia and can provide interesting links to other primary sources. Please use appropriate caution when viewing articles on Wikipedia)

Thanks again to everyone who guessed in this week’s “Identify It!” challenge. Keep an eye on the Harris Educational fan page on Facebook for the next “Identify It!” later next week.

Have a wonderful Thanksgiving everyone!



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