Yooperlite (Sodalite-rich Syenite)

Physical Properties

Hardness: 5.5-6 (Mohs); Color: Gray or mottled under daylight, glows bright orange/yellow under long-wave UV light; Luster: Vitreous to greasy; Crystal structure: Isometric (sodalite components); Specific gravity: 2.56-2.69

Formation & Geological History

Formed from alkaline magma chambers in the Earth's crust. Most specimens were glacially transported from the Superior Province of the Canadian Shield (specifically the Coldwell Alkaline Complex) during the last ice age.

Uses & Applications

Primarily used as a collector specimen, in lapidary work for decorative objects, and occasionally in jewelry as polished stones or towers.

Geological Facts

The name 'Yooperlite' is a trademarked term coined in 2017 by Erik Rintamaki, who discovered these glowing rocks on a beach in Lake Superior. They are famous for their bioluminescent-like glow under UV light.

Field Identification & Locations

Identify in the field using a 365nm long-wave UV flashlight at night; the sodalite inclusions will fluoresce brightly. Common locations include the beaches of Lake Superior in Michigan's Upper Peninsula.

Identified on: 5/9/2026

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