September 16 – Unnatural History

Today’s factismal: When ice forms on a lake, it is a mineral. When ice forms in your freezer, it isn’t a mineral; it is just ice.

Today is National Collect A Rock Day, so why are we talking about minerals? Because most (but not all) rocks are made out of minerals. And minerals are pretty cool. The first thing that you need to know about minerals is that the stuff in your vitamins aren’t minerals (so much for truth in labeling). That’s because, in order to be a mineral, something has to have a definite chemical composition (e.g., NaCl for halite), defined physical characteristics (e.g., has a density of 3.52 g/cc for diamond), and must be naturally-occurring (i.e., created by Mama Nature). Because the “minerals” in your vitamins lack at least two of those characteristics, they aren’t real minerals even if they are chemically identical to the ones in nature. The same thing is true of ice; only the stuff that forms outside is naturally-occurring and so it is the only ice that is a mineral.

Rhodochrosite is a mineral that was discovered by citizen scientists (My camera)

Rhodochrosite is a mineral that was discovered by citizen scientists
(My camera)

Strangely enough, that last requirement doesn’t hold for rocks; you can have man-made rocks, just as you can have natural ones. Thus, concrete (which isn’t found in nature) is just as much a rock as asphalt (which forms near oil seeps). And, whether we’re talking about rocks or minerals, it turns out that citizen scientists have done an amazing amount of work. Most new minerals are actually discovered by citizen scientists, as are many new types of rock. Cool beans, huh?

Opal isn't a mineral because it doesn't have a regular structure (My camera)

Opal isn’t a mineral because it doesn’t have a regular structure (but it is pretty)
(My camera)

And the contributions of citizen scientists to the study of geology doesn’t stop there. For example, the folks at Geo-Wiki are using citizen scientists to help measure the amount and type of land cover. If you’d like to give them a hand, then hike over to:

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