This crystal was recovered from the preserved tissue of a bamboo coral collected from Alaska’s Aleutian Islands in the 1850’s. Bamboo corals are deep-sea gorgonians (or sea fans) in the family Isididae. They can be found as deep as 3500m in the Northeast Pacific. This particular bamboo coral is stored in the archives of the Invertebrate Zoology Department at the Smithsonian Institution National Museum of Natural History in Washington, DC.
The crystal in the image is about 100 microns across, or one-tenth of a millimeter. On the right you’ll see the laminar tuberculated texture of a tiny calcareous ‘bone’ called a sclerite. Sclerites are found in the coenenchyme and polyps of the octocoral colony. Sclerites are diagnostic structures used to identify and describe octocoral species.
The image was taken by Peter Etnoyer using the Smithsonian’s Amray brand Scanning Electron Microscope.