When I was given a grab-bag of rock specimens the other week, this piece of limestone studded with little Devonian corals caught my eye. A few quick tests told me I could try acid digestion on it, so that's what I did. See the process, the results and the trade-offs after I bathed it in hydrochloric acid.

Related:
The acid test
Oxalic acid treatment of minerals
Fossil collecting tools
Non-fossils
_{Thamnopora coral specimen — Geology Guide photo}

I spent a fair amount of my late teens visiting wild caves. Then I moved to a place with no caves, moved again, and many years later I'm not sure I could repeat anything I used to do underground. But I still enjoy a tour of a good show cave, especially when they lay on the science instead of the "this formation looks like Snoopy" stuff. And I can still put up a mean quiz on caves. Don't let the questions drive you BATS.

For me, the science news of the week was the Nature paper this week announcing that the genes of Emiliania huxleyi have been sequenced. "Ehux" is an extremely important member of the ocean's plankton that grows almost everywhere in the world and pulls carbon dioxide out of the water—and thus, indirectly, the atmosphere—to make those beautiful microscopic disks of calcite, called coccoliths, with which it clothes itself. That makes Ehux the foremost coccolithophore, a word every kid should know. Coccoliths accumulate into the rock known as chalk. The Cretaceous Period got its name from the Latin word for chalk. That means that the age usually known for its dinosaurs (and sometimes its ammonoids) is really the Age of Coccolithophores.

Anyway, Ehux is an important target for gene sequencing. The Nature paper, which notably is open-access, shows that this organism is unusually diverse and has a huge genome with a large number of "optional" genes. This kind of "pan genome" has not previously been found outside the bacteria. I urge you to puzzle your way through the paper as well as read some of the news stories about it.
_{Emiliania huxleyi — Gerhard Langer, Alfred Wegener Institute}

Simon Wellings, of the Metageologist blog, has finally addressed a key topic for the future of the geoscientific professions: are we properly fascinating our children with geology? Since kids avoid the outdoors these days and get their stimulation from video screens, his new post on the geology of children's entertainment is timely. Do the artists who keep our kids' attention care about rocks and landforms?

Wellings' touchstone is Leonardo da Vinci, who is considered by historians of science to be the first close observer of landscape. Leonardo did a good job on his rocks; the makers of The Octonauts—well, "if there is a geological advisor," Wellings says, "then they should be shot." But Pixar acquits itself well. Realistic landscapes and rocks are a strong test of an artist's skill. I've always thought that the manufacturers of those fake boulders you hide your house keys in could do a much better job.

Related:
Seeing Disney's "Dinosaur"
Quicksand in the movies and reality
"Volcano" and "Dante's Peak"
Geology and the movies
An artist's version of Plymouth Rock
Octonauts toys reviewed