Larvikite
Monzonite (Feldspar-bearing Igneous Rock) · Decorative Stone and Mineral Specimen
Crystal System
Triclinic and Monoclinic (Feldspars)
Mineral Group
Silicates - Tectosilicates
Chemical Formula
(Na,Ca)(Al,Si)4O8
Formation Process
Igneous intrusion from alkali-rich magmas, specifically forming a monzonite variety known as larvikite
About This Crystal
The carved skull object exhibits a polished surface with a mottled, grayish-black background interspersed with silvery-blue flashes and brownish-pink feldspar patches. It is opaque with a vitreous to pearly luster characteristic of polished feldspars.
Physical Characteristics
Body color ranges from dark gray to black with silvery-blue schiller effects; streak is white; cleavage is good in two directions (typical of feldspar); fracture is uneven to conchoidal; specific gravity is approximately 2.65 to 2.75; tenacity is brittle.
Optical Properties
Displays prominent labradorescence or chatoyant-like schiller effect caused by the interference of light in the micro-intergrowths of alkali feldspar and plagioclase (Schiller effect). Biaxial with variable refractive indices.
Hardness & Durability
Origin Region
Larvik region of Norway
Hardness & Durability
Mohs hardness is 6 to 6.5; moderate toughness; susceptible to sharp blows due to cleavage planes; suitable for carvings and jewelry with protective settings.
Care & Maintenance
Clean with warm soapy water and a soft cloth; avoid harsh chemicals, ultrasonic cleaners, and extreme temperature shocks; store separately to prevent scratching.
Rarity & Value
Common as a dimension stone and decorative material, but carved specimens vary in price based on craftsmanship, flash intensity, and size, generally ranging from affordable to moderately priced.
Special Characteristics
Notable for its distinct silvery-blue flash (Schiller effect) caused by perthitic intergrowths of feldspar, giving it a shimmering, iridescent appearance under directional lighting.
Lore & History
Widely used as an ornamental and architectural stone since the 20th century. In modern crystal healing, it is often associated with the root chakra, grounding energy, enhancing inner vision, and protecting the spirit, though these are traditional beliefs without scientific backing.