Polygons in the Smithsonian

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pyrite-dodecahedron-ancash-peruWhile we were in DC, we managed to sneak in a visit to the Museum of Natural History.  And right next to the Hope Diamond (which, umm, looked surprisingly small.  I’d envisioned something fist-sized, which goes to show how little I know about diamonds) there were some really cool rocks.

The first thing I saw were balalt columns.

columnsI got really excited because I wrote about last April and how they often form hexagons.  So I took a closer look:

pentagon-columnYup, a perfect hexagon pentagon.  But there were a few hexagons around it, and it was pretty neat looking.

Then I moved to the minerals.  There was some neat symmetry in these twin crystals:

twin-crystals-smithsonian

(Here’s the info on them.)

twin-crystal-sign

Then I saw cubes.  Lots and lots of cubes, because a bunch of crystals grow that way.  There was this Fluorite from Spur Mountain mine, Cave in Rock in Illinois.

Flourite cubes (Spur Mountain mine, Cave in Rock, Illinois)

And these cubes of fluorapophyllite from Poona, Maharashtra in India.They were clearer in real life.fluorapophyllite cube (Maharashtra, India)

Then there’s this fluorite in gypsum, which is neat both because the cube is embedded in a see-through rock and because it’s from Penfield, which is just down the street from Rochester.  Seriously, you could pretty much walk there, and it’s an easy bike ride.

Fluorite in Gypsum (Penfield, New York)

Does anyone know if these rocks are related to the stuff that’s in toothpaste?

If shiny is more to your liking, here’s a whole bunch of Galite cubes from Missouri.

galena-missouri

Here’s the sign.  I like taking pictures of signs.  Otherwise, how would you know that there’s sphalerite mixed in?

galena-sign

And then check out this Pyrite.  It grows in two ways:  cubes and dodecahedrons, and this photo shows examples of both.  I love pyrite.  pyrite-smithsonian

I can’t wait to go back to the Smithsonian again.

One Response to “Polygons in the Smithsonian”

  1. Carnival of Mathematics 47, where no, well… « JD2718 Says:

    […] but is looking for their names. They come from Time/Life’s archives. Ξ at 360 found some polygons in the Smithsonian. Any with 7 sides? Look at the photos closely. Vlorbik is having some issues with WordPress’ […]

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