Seagoing researchers raced to the Canary Islands in 2011 when an eruption began off the volcanic island of El Hierro. On arrival, they began to collect these weird floating rocks. Most of us would say "Cool, pumice!" on seeing these, but the experts said "Hmm" and "uh-oh" instead. It was the white fillingwas it a sign of rhyolite, a threat of unexpectedly explosive lava? It was not; instead it was a nice scientific puzzle whose solution is a new word for the lexicon: xeno-pumice. They're melted, puffed-up seafloor sediments in a fresh lava shell. See my new article for more details on this stuff.
Geologists, especially after a long day in the field, think about rocks in terms of food. These xeno-pumice bombs look like they ought to be edible, with their black-chocolate shells and cakelike interiors. They're something like frybread, except that the outer shell is a different material from the pith. I hope that they inspire some way-new cuisine chef, because I can't think of an exact duplicate from the world's kitchens.