igneous
Yooperlite (Fluorescent Sodalite-bearing Syenite)
Sodalite-rich Syenite
Hardness: 5.5-6 (Mohs); Color: Gray or mottled in daylight, glows bright orange/yellow under UV light; Luster: Vitreous to dull; Crystal structure: Isometric (for the sodalite inclusions); Specific gravity: 2.6-2.7
- Hardness
- 5
- Luster
- Vitreous to dull
Identified More igneous →
Explore Yooperlite (Fluorescent Sodalite-bearing Syenite) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 5.5-6 (Mohs); Color: Gray or mottled in daylight, glows bright orange/yellow under UV light; Luster: Vitreous to dull; Crystal structure: Isometric (for the sodalite inclusions); Specific gravity: 2.6-2.7
Formation & geological history
Formed through the cooling of alkaline magma deep within the earth, later transported and deposited as glacial till. These specific specimens are primarily found along the shores of Lake Superior, originally originating from the Grenville Province in Canada.
Uses & applications
Primarily collected as a novelty gemstone, used in jewelry (pendants, beads), and highly sought after by mineral collectors and hobbyists.
Geological facts
The term 'Yooperlite' was coined in 2017 by Erik Rintamaki, who discovered them using a UV light on a beach in Michigan's Upper Peninsula. The fluorescence is caused by the mineral sodalite.
Field identification & locations
Identified in the field by using a long-wave UV flashlight at night on gravel beaches. Without UV light, they look like ordinary gray stones. Common locations include the beaches of Lake Superior in Michigan and Ontario.
