igneous
Yooperlite (Fluorescent Sodalite-bearing Syenite)
Sodalite-rich Syenite (Syenite with Na8(Al6Si6O24)Cl2 inclusions)
Hardness: 5.5-6 on Mohs scale. Color: Gray/mottled black in daylight; glows bright orange/yellow under UV light. Luster: Dull to Vitreous. Structure: Granular/Phaneritic.
- Hardness
- 5
- Color
- Gray/mottled black in daylight
- Luster
- Dull to Vitreous
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Physical properties
Hardness: 5.5-6 on Mohs scale. Color: Gray/mottled black in daylight; glows bright orange/yellow under UV light. Luster: Dull to Vitreous. Structure: Granular/Phaneritic.
Formation & geological history
Formed from molten rock (magma) that cooled slowly underground. These specific specimens were transported from Ontario, Canada, via glacial movements during the last ice age, eventually depositing on beaches in the Great Lakes region.
Uses & applications
Primarily used for geological collecting, decorative lapidary work, and jewelry. They are highly sought after by rockhounds due to their unique fluorescent properties.
Geological facts
These rocks were 'discovered' and branded in 2017 by Erik Rintamaki on the shores of Lake Superior. The 'glow' is caused by the mineral Sodalite, which reacts to long-wave ultraviolet light.
Field identification & locations
Identify in the field by using a 365nm UV flashlight at night on gravel beaches. Look for bright orange 'ember' like spots. Common locations include the southern shores of Lake Superior in Michigan's Upper Peninsula.
