Table of Contents

• From the Editor — “Ohwa Tagu Siam” by Howie Green 1
• Deep-Red Fluorescent Fluorite from Mapimi, Mexico (and Elsewhere): A Case of an “Electronic Defect” as an Activator by Glenn Waychunas 2–7
• FMS Membership Responds: Red Fluorescent Fluorite by — 8–16
• Colorado’s Crystal Cities by William “Crystal Bill” Kaunitz and Stuart Gehrke 17–25

From the Editor — “Ohwa Tagu Siam”

By Howie Green · p. 1

A Tucson mineral-show story recounts how red-fluorescing fluorite initially appeared inactive under longwave illumination, then glowed again after shortwave ultraviolet exposure. The unexpected recovery led the editor and fellow collectors to investigate the dealer’s stock and became a recurring anecdote among fluorescent-mineral collectors. The column introduces Glenn Waychunas’s feature article, which explains the electronic-defect mechanism behind the bleaching and reactivation.

Deep-Red Fluorescent Fluorite from Mapimi, Mexico (and Elsewhere): A Case of an “Electronic Defect” as an Activator

By Glenn Waychunas · pp. 2–7

Red-emitting fluorite from Mapimi and other localities owes its changeable glow to sodium-stabilized M-centers, clusters of anion vacancies produced in fluorite’s electronic structure. Longwave ultraviolet exposure bleaches the red emission by redistributing or disrupting trapped electrons, while shortwave ultraviolet can restore it. The article explains the proposed defect and energy-transfer processes, distinguishes M-center emission from other red or orange activators, and compares specimens from Mexico, Morocco, Pakistan, Canada, and other localities.

FMS Membership Responds: Red Fluorescent Fluorite

pp. 8–16

Fluorite specimens and observations contributed by FMS members illustrate red emission, bleaching, reactivation, and color zoning across multiple localities. Images and spectra show a Pakistan specimen changing after shortwave exposure, Mapimi and Melchor Múzquiz material responding to recharging, and examples from Morocco, Illinois, Belgium, and unidentified sources. The contributions also document differences among specimens, including fading white-light color, persistent alternate emissions, fluorescent phantoms, and suspected artificial irradiation.

Colorado’s Crystal Cities

By William “Crystal Bill” Kaunitz and Stuart Gehrke · pp. 17–25

Quartz crystals from the Subway Pocket on Colorado’s Mount Antero form striking parallel clusters on microcline feldspar, with green fluorescent phantom layers and miniature city-like patterns. The article recounts the pocket’s discovery and demanding high-altitude recovery, then examines the crystals’ inclusions, growth relationships, and varied responses to ultraviolet and white light. The green fluorescence is attributed to uranyl ions, although the exact inclusion species remains unidentified; chlorite, rust-colored silica, and fluorescent feldspar add further detail to the specimens.