Yooperlite (Sodalite-bearing Syenite)
Sodalite-bearing Syenite (Fluorescent Sodalite in Syenite) · Mineral Specimen and Decorative Stone
Crystal System
Isometric (for Sodalite inclusions); the surrounding rock is a coarse-grained igneous phaneritic mass.
Mineral Group
Silicates (Tectosilicates); specifically Sodalite group and Feldspar group within an igneous matrix.
Chemical Formula
Na8(Al6Si6O24)Cl2 (Sodalite) within an Alkali Feldspar-rich silicate rock matrix
Formation Process
Igneous. Formed from alkaline magmas lacking silica (silica-undersaturated). The resulting syenite contains sodalite grains that replaces other minerals during cooling.
About This Crystal
A mottled, coarse-grained igneous rock appearing as a dark grey-to-black sphere in normal light. It features a speckled or porphyritic appearance with visible patches of minerals. When viewed under long-wave ultraviolet light, the sodalite grains fluoresce intensely.
Physical Characteristics
Color: Grey, black, and dull white in daylight. Streak: White. Cleavage: Poor (Sodalite) to perfect (Feldspar). Luster: Vitreous to dull. Specific Gravity: ~2.6-2.7. Fluorescence: Vibrant orange/yellow under 365nm UV light.
Optical Properties
Isotropic (Sodalite) and anisotropic (Feldspar) components. The primary optical phenomenon is intense LWUV fluorescence (long-wave UV luminescence) caused by sulfur or chloride activators in the sodalite.
Hardness & Durability
Origin Region
Primarily the Upper Peninsula of Michigan, USA (Lake Superior shores); also documented in Ontario, Canada, and Greenland.
Hardness & Durability
Mohs hardness 5.5 to 6.0. It is moderately durable but can be scratched by harder gemstones like quartz or topaz. Brittle tenacity.
Care & Maintenance
Clean with warm soapy water and a soft cloth. Avoid harsh chemicals and ultrasonic cleaners which may penetrate cracks in the syenite matrix. Store separately to avoid scratching.
Rarity & Value
Common to Uncommon. While syenite is common, the specific fluorescent variety found in the Great Lakes region is a popular collector's item. Value is based on the concentration and brightness of the fluorescent spots.
Special Characteristics
Strong tenebrescence or photochromism in some variants, and iconic brilliant orange-yellow fluorescence under UV light, often appearing like glowing lava embers.
Lore & History
Discovered/Popularized by Erik Rintamaki in 2017 in Michigan. Traditionally associated with the Throat Chakra, it is believed by modern practitioners to encourage self-expression and 'shedding light' on hidden truths.