DigMyGem Gem encyclopedia

Yooperlite

Other Silicates & Gemstones

Yooperlite is a trade name, not a mineral species. It refers to gray syenite pebbles and cobbles containing abundant fluorescent sodalite, whose patches glow orange to orange-red under short-wave ultraviolet light while remaining much less conspicuous in daylight.

Identity

Material or variety
Sodalite-bearing syenite
Scientific or material identity
Fluorescent sodalite-bearing syenite
Classification
Rock or mixed mineral material
Composition or formula
Mixed igneous rock
Crystal system or structure
Aggregate or composite structure
Geological or manufacturing origin
Forms in igneous rock or volcanic material.
Mohs hardness
5.5 to 6

Origins

Canada · USA

Appearance & optical properties

gray speckled syenite with orange fluorescent sodalite patches.

History & discovery

Collector Erik Rintamaki introduced the name after finding many ultraviolet-reactive pebbles on a Lake Superior beach in Michigan in 2017. Geological work later identified them as sodalite-bearing syenite glacial erratics and proposed source rocks in Ontario's Coldwell Alkaline Complex, though the precise source remains under study.

Uses & care

Common uses
The pebbles are collected and polished as fluorescent display stones, and their easy ultraviolet identification also supports geology teaching and citizen-science mapping around the Great Lakes.

Jewellery

5 pieces of Yooperlite jewellery. Learners earn each one in DigMyGem by learning words; until then it shows as a silhouette.

  • Silhouette of Gitche Gumee Pendant

    Gitche Gumee Pendant

    Pendant

    A pebble of grey yooperlite from the shores of Lake Superior, polished just enough to show the orange sodalite eyes that blaze under ultraviolet light. It is set in a rough silver bezel.

  • Silhouette of Yooper Beacon Ring

    Yooper Beacon Ring

    Ring

    A chunky silver ring around a yooperlite cabochon that looks dull in daylight and lights up in orange flames beneath a UV lamp. It is a novelty for rock collectors.

  • Silhouette of Lake-Fire Brooch

    Lake-Fire Brooch

    Brooch

    A brooch shaped as a north-country pine, its trunk a narrow sliver of yooperlite. The stone's hidden glow is the piece's secret.

  • Silhouette of Lakeshore Glow Necklace

    Lakeshore Glow Necklace

    Necklace

    An imagined necklace of grey Lake Superior pebbles that glow with orange flecks under ultraviolet light, as yooperlite does.

  • Silhouette of Lake Superior Tiara

    Lake Superior Tiara

    Tiara

    An imagined silver tiara of grey Lake Superior stones that glow with orange flecks under ultraviolet light.

Sources