Microminerals

摘要

A while ago, I was working away at the microscope when an insect suddenly appeared in my field of view. This happens to all of us from time to time. Usually, it's a tiny wanderer from field collecting, and though startling, it's not surprising. This one, however, was a surprise. It was dead, and it was not on the specimen, but in the specimen. As Figure 1 shows, it was under a layer of thermonatrite (Na_2CO_3 centre dot H_2O). Thermonatrite usually derives from the dehydration of natron (Na_2CO_3 centre dot 10H_2O), and there's plenty of natron in Mont Saint-Hilaire, where the specimen originated. The origin of the thermonatrite was clear. What was not clear (and still isn't) is why the insect was under the thermonatrite and not on top of it. Thermonatrite effloresces from cracks containing natron, but it shouldn't be climbing on top of things like bugs. A quick check with the Canadian Museum of Nature revealed that the insect was a silken fungus beetle (Cryptophagidae, probably caenoscelis), possibly from the forest floor above the quarry. As a bio-mineral specimen, it doesn't equate to malachite pseudomorphs after mice (like the one Rock Currier once reported having seen in the Fers-man Museum in Moscow), but at 2 mm from stem to stern, it's the right scale for micromounters!