Curio Cabinet: Fluorite

CC fluorite

The Curio Cabinet series (#curioTuesday) is published biweekly, featuring an artifact of natural or cultural history and a brief selection of nifty facts. Curio Cabinet celebrates the history of curio collections, the roots of which played a part in the globalization of learning and scientific knowledge. Learn more here.

Today’s curio: fluorite
Type: mineral
Origin: found worldwide
Size: approx. 2 in long x 1 in tall

Fluorite is the most common rock you don’t know about. Actually, I take that back – you probably already know a bit about it without realizing it. Deposited by hydrothermal processes and sometimes found in limestones and dolomites, this mineral is also called fluorspar, and gives us the root of the word “fluorescence” for its neato ability to glow blue under UV light.

Fluorite is the only common mineral with four directions of perfect cleavage, meaning that it can create these uber-awesome natural octahedrons.

Fluorite octahedrons. Ryan Salsbury, Creative Commons

Fluorite octahedrons. Ryan Salsbury, Creative Commons

Color is not a good way to identify fluorite, although common colors include purple, green, yellow, or a banded mixture of colors. Here’s a Google images snapshot of just some of the different colors fluorite comes in:

We use fluorite in a number of ways:

1. Lenses. Because of its low dispersal and low refractive qualities, fluorite makes for good microscope and telescope lenses.
2. Fluoride. Fluoride is a chemical derived from fluorite that is said to protect tooth enamel.
3. Iron, steel, and the production of other metals. Fluorspar is added to the metallurgic process to help remove impurities; between 20 and 60 pounds of fluorspar is used for every ton of metal produced!

We use it in the production of fluorocarbon derivatives in solvents, refrigerants, and anesthetics. Remember chlorofluorocarbons, the toxic greenhouse gas that used to pump out of every fridge and air conditioner? Yeah, we failed on that one.

Fluorite is also used in a lot of jewelry: it’s turned into beads and tumbled gemstones and cabochons for its variety of light colors and transparency. It’s too soft to be used more widely (rates a 4 on the Mohs scale) but you have to admit, it does make for some pretty embellishments. I think my favorite is that reddish-pink on in the top left.

Faceted fluorite gems, from the Smithsonian National Museum of Natural History

Faceted fluorite gems, from the Smithsonian National Museum of Natural History

Thanks for joining us for #curioTuesday! Interested in having something from your collection featured? Email us with a bit about yourself and your curio.

Posted on June 3, 2014, in Curio Collection and tagged , , , , , , , , , , . Bookmark the permalink. 1 Comment.

  1. The Curio Cabinet is a wonderful resource for naturalists who may need to identify objects in the field. Please be sure to mention on your postings the Leave No Trace Outdoor Ethic of Leave What You Find. I believe we need a cultural shift from collecting to photographing so that future generations can share the joy of finding natural objects, like fluorite crystals, rather than be restricted to finding such things only in museums.

    Don Callihan

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