mineral
Fluorescent Calcite in Limestone (or Yooperlite / Syenite pebble)
Calcite (CaCO3) / Fluorescent Sodalite-bearing Syenite
AI-generated identification · may be incorrectHardness 3 (if calcite) to 5.5-6 (if sodalite/syenite); dull to vitreous luster; exhibits noticeable fluorescence/phosphorescence under ultraviolet (UV) illumination displaying warm yellowish-white to orange glowing patches; crystalline to massive granular texture.
Identified More mineral →
Explore Fluorescent Calcite in Limestone (or Yooperlite / Syenite pebble) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness 3 (if calcite) to 5.5-6 (if sodalite/syenite); dull to vitreous luster; exhibits noticeable fluorescence/phosphorescence under ultraviolet (UV) illumination displaying warm yellowish-white to orange glowing patches; crystalline to massive granular texture.
Formation & geological history
Formed either as a sedimentary/hydrothermal calcium carbonate deposit (calcite) or within alkaline intrusive igneous rocks (sodalite-bearing syenite) that have been glacially transported and eroded into rounded cobbles.
Uses & applications
Primarily sought after by mineral collectors and UV fluorescence hobbyists; used in educational geology displays; polished for ornamental novelties.
Geological facts
Many common minerals like calcite, fluorite, and sodalite fluoresce brightly under shortwave or longwave ultraviolet light due to activator ions such as manganese, europium, or disulfide radicals. Rocks known as 'Yooperlites' are famous for glowing under 365nm UV light along the beaches of Lake Superior.
Field identification & locations
Identified in the field by sweeping gravelly beaches or rock outcrops at night using a specialized 365nm UV flashlight, causing the mineral inclusions to glow distinctly against dark surroundings.
