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Locality: Pilot Knob Tailings (Lower Ore Body), Iron County, Missouri
Weight: 89 Grams
Dimensions: 2.25" x 1.75" x 1.5"
Minerals Present: Magnetite (after Actinolite), Fluorapatite, Ferruginous Quartz, Albite.
Reactivity: Strong Neon-Green UV Fluorescence; Non-Reactive to Acid.
This is an exceptional representative specimen from the historic and restricted Pilot Knob Magnetite (PKM) deposit in Southeast Missouri. This "Iron Oxide-Apatite" (IOA) rock captures a complex 1.4-billion-year-old hydrothermal replacement of volcanic ash.
Key Features of this Specimen:
Acicular Magnetite: The black, needle-like crystals are magnetite pseudomorphs after Actinolite, showing a "tourmaline-like" structure with a diagnostic jet-black streak.
"White Tube" Replacement: Distinctive white tubes of Quartz/Albite run through the magnetite, marking the original pathways where mineral-rich fluids replaced the volcanic tuff.
Electric UV Fluorescence: Features numerous spots of Fluorapatite that glow a brilliant, "crazy" neon green under UV light. These spots are known indicators of Rare Earth Elements (REEs) like Cerium and Lanthanum.
Red Barrel Crystal: Includes a striking, red barrel-shaped crystal (Ferruginous Quartz) embedded in the matrix. This crystal is non-reactive to acid, confirming its silica-rich mineralogy.
This is a must-have for collectors of Missouri minerals, fluorescent specimens, or those interested in the USGS-designated "Critical Minerals" of the St. Francois Mountains.
