Calcite replacing Septarian Nodule ("Melicaria") (ex Dr. Wouter van Tichelen Collection)

Item Description

These specimens have been labeled as Quartz pseudomorphs or "casts", but they are actually Calcite, as they react to hydrochloric acid. They are according to former Smithsonian mineral curator, John White, a replacement of "the crack-filling of a septarian nodule or possibly after a similar crack-filling spherulite". Essentially an intrusion of Calcite filled in a septarian nodule, which later dissolved away leaving the internal form completely preserved and intact. They are unique in the mineral world, and certainly beautiful as they have a form that unlike anything we've seen. The hollow chambers almost give the impression of something organic, like some kind of aquatic life or the cells of a bee colony. The piece is a complete "floater", crystallized all around with no damage or point of attachment. It is said that these specimens are called "melicaria" ("melikaria" on the label) after the grandmother of the man in Mexico who discovered them. From the noted pseudomorph collection of Dr. Wouter van Tichelen of Belgium.