Specimen of the Month: It Glows!

Here is a question: how long would the Museum be able to showcase a different specimen if just one were on display each month?

Without the ability to allow every specimen on the exhibit floor at once, curators must make difficult decisions. Some specimens simply don’t fit a display theme. Some literally do not fit—certain animals magically become much larger when one tries to work them into a tight space. Despite having amazing qualities, specimens won’t always make the cut, however they do have a chance at becoming the next specimen showcased on its own in the Museum lobby.  Here, a single-specimen display has been greeting visitors for some years, known as the Specimen of the Month. To answer the question, the Museum’s current collection could sustain a new Specimen of the Month for nearly three hundred years without repeating even once.

It would be amiss to bring up the Specimen of the Month without directing readers’ attention to one of these specimens. Meet calcite, the magical member of our geology collection that glows, and April’s showcased specimen. The specimen is a broken geode, an unassuming rock formation of beautiful crystals hidden within. Geodes began long, long ago as igneous or sedimentary rocks.  Air or gas built up to create a cavity inside the rock. A crusty outer layer then formed, and finally groundwater full of dissolved minerals seeped inside. After only some thousands to a million years, a geode is born. Luckily for humans, geodes should only take a few minutes to break open, exposing the wonderful inner calcite crystals.

Other mesmerizing qualities of this carbonate mineral can be revealed after just some tinkering. When heated, it emits light, much like that of heated metals. Calcite also has a property called photoluminescence. To witness this, one may simply take a piece of calcite and hold it under a black light in a dark room.  The result is calcite absorbing ultraviolet light and immediately emitting light of a different wavelength. The photoluminescence will usually appear as a brilliant blue or magenta. As staff, it’s rather amusing to be able to share with visitors that some of our rocks glow.

The Museum will continue to showcase this calcite geode, highlighting more of its unique qualities, for a few more weeks before returning it to storage with over 500 other rock and mineral specimens. If visitors are ambitious, they may venture to the online database to view a majority of the Museum’s specimens, or can stop by to see our other displays. The Museum attempts to expose the public to as much of its collections as possible, whether through long-term exhibits, Specimen of the Month, or virtual means of exploration.  For some fifty years now, the staff has been proud to present the unique stories of the Northwoods’ seemingly endless amount of natural wonders.