igneous
Yooperlite (Sodalite-bearing Syenite)
Sodalite-rich Syenite (Na8(Al6Si6O24)Cl2)
Hardness: 5.5-6.0 (Mohs); Color: Gray or speckled brown in daylight, glowing neon orange under 365nm UV light; Luster: Vitreous to dull; Crystal structure: Isometric (sodalite inclusions); Specific gravity: 2.6-2.7
- Hardness
- 5
- Luster
- Vitreous to dull
Identified More igneous →
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Physical properties
Hardness: 5.5-6.0 (Mohs); Color: Gray or speckled brown in daylight, glowing neon orange under 365nm UV light; Luster: Vitreous to dull; Crystal structure: Isometric (sodalite inclusions); Specific gravity: 2.6-2.7
Formation & geological history
Formed through slow crystallization of alkaline magma deep within the crust. These specific specimens are often found as glacial erratic and were transported from the Canadian Shield (approx. 1 billion years old) to the Great Lakes region during the last ice age.
Uses & applications
Primarily used as a collector's specimen and in lapidary work for jewelry and decorative carvings (like the tower shown). High value in the metaphysical/crystal healing community.
Geological facts
They were discovered/trademarked by Erik Rintamaki in 2017 on the shores of Lake Superior. While they look like ordinary gray rocks in daylight, they fluoresce brilliantly under long-wave ultraviolet light due to the presence of fluorescent sodalite.
Field identification & locations
Identify in the field using a 365nm UV flashlight at night; they will pop with bright orange spots. Common on the beaches of Lake Superior in Michigan's Upper Peninsula. Collectors should look for high concentration of 'glow' spots.
