Table of Contents

• From the Editor—‘Elementary, My Dear Watson’ by Howie Green 1–5
• Luminescence Zoning in Minerals by Glenn Waychunas 6–9
• Ludlow Diamonds and Other Multi-Generational Fluorescent Calcite by Chris Clemens 9–13
• Every Fluoro Tells a Story—Scheelite from the Conchita Mine by Daniel Callado Montero 13–14

From the Editor—‘Elementary, My Dear Watson’

By Howie Green · pp. 1–5

Palmarejo Mine calcite illustrates how trace elements and changing growth conditions produce sharply contrasting fluorescent generations. The article examines orange-red fluorescence associated with manganese activated with lead, and the manganese oxide layers that mark boundaries between calcite growth stages. Spectral analysis of later calcite shows strong lead and cerium emissions contributing violet light, while also addressing the possible roles of manganese concentration and Pb–Mn energy transfer. The discussion places these findings in the broader chemistry of mineral luminescence.

Luminescence Zoning in Minerals

By Glenn Waychunas · pp. 6–9

Luminescence zoning records changes in crystal growth conditions and can reveal variations in activators, co-activators, quenchers, and included impurities. The article explains concentric and sector zoning, showing how growth-solution changes and selective uptake at crystal faces create patterns in minerals such as fluorite, apatite, gypsum, and aragonite. It also considers zoning in afterglow and the formation of luminescent crystal phantoms. These features can preserve evidence of a crystal’s growth history and changing chemical environment.

Ludlow Diamonds and Other Multi-Generational Fluorescent Calcite

By Chris Clemens · pp. 9–13

Ludlow diamonds are fluorescent calcite crystals enclosed by later, weakly fluorescent calcite, producing bright diamond-shaped cross sections when specimens are cleaved. Their formation involves an initial manganese- and lead-bearing calcite generation, manganese oxide coatings, and subsequent calcite overgrowth. The article compares these rare California specimens with twinned calcite from the Palmarejo Mine and mariposa calcite from Santa Eulalia, Mexico. In all three, successive growth stages create contrasting fluorescent zones and distinctive internal crystal outlines.

Every Fluoro Tells a Story—Scheelite from the Conchita Mine

By Daniel Callado Montero · pp. 13–14

Scheelite from the Conchita Mine in Andalusia, Spain, combines a history of tungsten mining with a characteristic blue-white short-wave ultraviolet response. The article traces the deposit’s early identification and later exploration, including its importance as a tungsten source during the 1920s and the wartime demand for the metal. It also explains that scheelite is calcium tungstate and that the tungstate ion produces its fluorescence. The mine’s abandoned, poorly ventilated workings are noted as unsafe to visit.