Rocks

On our recent trip to the Smithsonian, we saw just a fraction of the natural history museum. We ended up spending most of our time in the invertebrate and geology exhibits. Ava loved the live tarantulas so much, she asked for a Mexican orange-kneed—not a pink toe—variety for a pet. And as for the rocks, all three of us were mesmerized by the meteorites, gems, and minerals.

Here’s a picture of a section of columnar dacite. What’s so interesting to me about it is how it’s formed from lava flow and its mathematical properties. When the lava cools, it shrinks and fractures creating vertical columns of crystallized dacite in various polygon shapes.