Table of Contents

• Fluorescence and Phosphorescence in the Sicilian Chalky-Sulphiferous Formation by Vincenzo Arcoleo 1–6
• From the Editor—“No Good Deed Goes Unpunished” by Howie Green 7–11
• Activators in Willemite from the Republic of the Congo by Mike Crawford 12–13
• How Hot Are Your Rocks? Radioactivity in Uranyl-Activated Fluorescent Minerals by Chris Clemens 13–19
• Fluorescent Chalcedony & Calcite of Northwest Nebraska by Brian Walko 20–25
• Mining Uranium-101 by Howie Green 26–28

Fluorescence and Phosphorescence in the Sicilian Chalky-Sulphiferous Formation

By Vincenzo Arcoleo · pp. 1–6

Fluorescence and phosphorescence in celestine, gypsum, calcite, and aragonite from Sicily’s chalky-sulphurous formation can help distinguish minerals and zones within complex specimens. Observations from the Muculufa mine and Cozzo Disi sulfur mine show that Sicilian material may fluoresce under ultraviolet light and produce green phosphorescence, while comparable minerals from other regions often lack that response. The article considers the formation and coloration of celestine and proposes that sulfur, possibly alongside trace lanthanides, contributes to the observed luminescence.

From the Editor—“No Good Deed Goes Unpunished”

By Howie Green · pp. 7–11

A collaborative Tucson mineral-show search yields two upgrades for an absent collector: willemite-bearing specimens from Gotala, Republic of the Congo, and a large Book Cliffs, Colorado, barite on matrix. The account contrasts competitive buying with group cooperation, recounting how friends assessed a reserved lot, located another dealer’s specimens, and found the sought-after barite. It also notes the specimens’ fluorescent responses, including willemite’s pale-green shortwave and yellow medium- and longwave emissions, and reflects on friendship and shared collecting.

Activators in Willemite from the Republic of the Congo

By Mike Crawford · pp. 12–13

Spectral measurements of willemite from Gotala, Mindouli, Republic of the Congo, show a broad shortwave emission centered near 500 nm, unlike the sharper green peak of Franklin, New Jersey, willemite. The specimen also fluoresces yellow under medium- and longwave ultraviolet light and has a modest afterglow. The article compares these responses with calcite in the same specimen and considers manganese and possible additional activators, including arsenic, as explanations for the willemite’s broader color and wavelength-dependent fluorescence.

How Hot Are Your Rocks? Radioactivity in Uranyl-Activated Fluorescent Minerals

By Chris Clemens · pp. 13–19

A survey of 16 green-fluorescent specimens measures radioactivity in minerals activated by uranyl, distinguishing uranium present as a trace contaminant from uranium integral to a mineral’s structure. Structurally uranium-bearing species, including autunite, produced the highest readings, while some fluorescent opal and chalcedony specimens registered little or no radioactivity above background. The article explains the measurement method, summarizes results, and discusses handling precautions related to dust, ingestion, radon, and prolonged close exposure, emphasizing that risk varies with uranium content and specimen conditions.

Fluorescent Chalcedony & Calcite of Northwest Nebraska

By Brian Walko · pp. 20–25

Watermelon chalcedony veins near Toadstool Park, Nebraska, contain chalcedony along their edges and calcite in their centers, producing vivid green and red fluorescence under mediumwave ultraviolet light. The article outlines the geology of the White River Group and Chadron Formation, explains how mapped veins were located in the field, and recounts daytime and nighttime prospecting. Specimens collected include weathered veins, brecciated chalcedony and calcite, botryoidal chalcedony on calcite, and calcite with chalcedony veinlets, with practical guidance on timing and field conditions.

Mining Uranium-101

By Howie Green · pp. 26–28

The Crow Butte uranium operation near Crawford, Nebraska, provides a case study of in-situ recovery and the wider uranium fuel cycle. The article explains how oxygen- and bicarbonate-treated groundwater dissolves uranium in underground sandstone deposits, which is then pumped to the surface, captured on resin, and processed into yellowcake. It also reviews uranium’s oxidation states, the formation of fluorescent uranyl-bearing chalcedony, and subsequent conversion and enrichment steps for nuclear fuel. The discussion places Crow Butte production in the context of domestic uranium supply.