Aunumnite

Aunumnite is a fictional mineral species described in mineralogical texts and educational materials as a hydrated uranium-bearing phosphate. It is designed to illustrate standard methods of mineral description and classification and is not known to occur in the natural world.

Composition and structure: The nominal formula is given as Ca(UO2)2(PO4)2·8–10H2O, with variations in water content. The mineral is described as forming a layered uranyl phosphate framework in the tetragonal crystal system. Common crystal habits include slender tabular crystals and radiating aggregates. Physical properties include a glassy (vitreous) luster, a yellow to olive-yellow color, and a Mohs hardness of about 3.5 to 4. Specific gravity is typically in the 4.2–4.8 range. It is radioactive due to its uranium content.

Occurrence: In the fictional setting, aunumnite is reported from hydrothermal veins and phosphate-rich deposits in the region of Aunumna. It is often found with related uranium phosphates and secondary alteration products.

Etymology and history: The name derives from the fictional region of Aunumna. It was first described in the literature by Dr. S. K. Vale in 2019 as a teaching example and has since appeared in geology textbooks and databases as an illustrative mineral species.

Applications and safety: Because of its assumed uranium content, aunumnite would be handled with radiological precautions similar to real uranium minerals. In fiction, it serves to demonstrate how to report chemical, physical, and radiological properties in a consistent manner.