A glauberite crystal cluster replaced by aragonite and/or calcite. (These specimens are frequently visually identified as one of these species without any evidence, despite the fact that visual differentiation is impossible in this case.) Bright white fluorescence under both longwave and shortwave UV. Note the rough morphology, which is unusual. The majority of these specimens offered are usually smooth, with distinct aragonite/calcite (or even gypsum) crystals invisible. One incomplete termination reveals the internal crystalline structure.