Yooperlite (Sodalite-bearing Syenite)
Sodalite-bearing Syenite (Fluorescent Sodalite in Syenite) · Collector Mineral / Fluorescent Mineral Specimen
Crystal System
Sodalite is Isometric (cubic), occurring here as disseminated grains within a Phaneritic (crystalline) igneous rock matrix.
Mineral Group
Silicates; Sodalite is a Tectosilicate (Feldspathoid), Syenite is a Plutonic Igneous Rock.
Chemical Formula
Complexity of Syenite (Feldspar: (K,Na)AlSi3O8 + Sodalite: Na8Al6Si6O24Cl2)
Formation Process
Igneous formation; specifically cooling of alkaline magma in deep-seated plutonic environments forming syenite, with sodalite crystallizing as a minor constituent.
About This Crystal
A mottled grey, black, and reddish-brown rock with a grainy texture. Opaque with a dull to vitreous luster. Carved into a character shape, appearing as a standard igneous rock under white light.
Physical Characteristics
Body color is mottled grey and brownish-red (likely from iron staining). Streak is white. Specific gravity is approximately 2.6-2.7. Non-magnetic. Exhibits intense orange fluorescence under Longwave UV (365nm) light.
Optical Properties
Under normal light, it shows standard stony reflection. The key optical phenomenon is Tenebrescence or high-intensity Photoluminescence (fluorescence) where sodalite grains glow brilliant orange-yellow.
Hardness & Durability
Origin Region
Primarily the Upper Peninsula of Michigan (Lake Superior shores), USA; also found in glacial drifts across the Midwest and Ontario, Canada.
Hardness & Durability
Mohs hardness of 5.5 to 6. Durable enough for handling but can be scratched by quartz or hardened steel. Fairly tough due to the interlocking crystalline structure of the syenite host.
Care & Maintenance
Wash with warm soapy water and a soft brush. Avoid harsh chemicals or acids which can dull the sodalite. Keep away from extreme heat to prevent cracking of the rock matrix.
Rarity & Value
Locally common but globally unique to specific alkaline rock provinces. Value is moderate, primarily driven by the quality of the carving and the intensity/density of the fluorescent sodalite 'spots'.
Special Characteristics
Strong Orange Fluorescence under UV light (caused by sulfur impurities in the sodalite lattice). Some specimens may show minor phosphorescence.
Lore & History
Discovered/branded in 2017 by Erik Rintamaki on the shores of Lake Superior. Historically, sodalite was used for jewelry, but this specific fluorescent syenite mix is a modern lapidary favorite associated with 'light within' and self-discovery in contemporary lore.