The good Samariumitan's Aragonite

Samarium drives the fluorescence of this aragonite/calcite.

It's more of a mix, phases of the carbonates, rather than any pure mineral.

More about this specimen on the MKA fluorescent minerals website.

A spectrum revealing the activator is available for download.

Locality: Bocchegiano Mines, Tuscanny, Italy

Source: Fluorescent Minerals Workgroup MKA.