Igneous

Sodalite Syenite (popularly known as Yooperlite)

Sodalite-rich Syenite (composed of alkali feldspar and sodalite)

Hardness: 5.5-6 on the Mohs scale. Color: Grayish-black under normal light, vivid glowing orange/red under long-wave ultraviolet light. Luster: Vitreous to greasy. Crystal structure: Hexagonal/Cubic (inclusions). Cleavage: Poor.

Hardness: 5
Luster: Vitreous to greasy

Identified March 30, 2026More igneous →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Formed from alkaline magma reaching the Earth's crust. These specific specimens were transported by glaciers during the Pleistocene epoch from Canada to the Upper Peninsula of Michigan, where they are found as water-worn pebbles.

Uses & applications

Primarily used as a collector mineral and in the lapidary arts for making jewelry, polished stones, and decorative spheres due to its unique fluorescence.

Geological facts

Was first 'discovered' and branded in 2017 by Erik Rintamaki on the shores of Lake Superior. The 'glow' is caused by trace amounts of the mineral sodalite reacting to UV light.

Field identification & locations

Identify in the field using a long-wave 365nm UV flashlight at night on gravel beaches. Common locations include the southern shores of Lake Michigan and Lake Superior. Collectors look for high concentrations of fluorescent 'flakes' or solid glowing patterns.

Other igneous specimens

See all

Blue Apatite

Fluorapatite (Ca5(PO4)3F)

mineral

Dark Igneous Rock (Likely Basalt or Diabase)

Basalt (extrusive igneous rock) or Diabase (intrusive igneous rock - also known as Dolerite), largely composed of plagioclase feldspar, pyroxene (augite), and sometimes olivine and amphibole. Exact mineralogy would require thin section analysis.

Igneous

Magnetite

Iron(II,III) oxide (Fe3O4)

mineral

Sodalite

Sodalite - Na8(Al6Si6O24)Cl2

mineral

Blue Apatite

Apatite (Group), Ca5(PO4)3(F,Cl,OH)

mineral

Magnetite

Magnetite (Fe3O4)

mineral