Sugilite
Sugilite · Semi-Precious Gemstone and Collector Mineral
Crystal System
Hexagonal system, typically found as massive or compact crystal habits rather than distinct visible crystals.
Mineral Group
Silicates, specifically the milarite group of cyclosilicates.
Chemical Formula
KNa2(Fe,Mn,Al)2Li3Si12O30
Formation Process
Metasomatic replacement in manganese-rich rocks and crystallization in cavities of alkali granite pegmatites.
About This Crystal
This is a tumbled specimen displaying a vibrant purplish-blue to magenta body color with characteristic mottled swirls, cloud-like patches, and dark inclusions. It has an opaque to translucent appearance and a polished, waxy to sub-vitreous luster typical of tumbled silicate stones.
Physical Characteristics
Body color ranges from deep magenta, reddish-purple to intense purplish-blue. Streak is pale pink to white. Cleavage is poor to none, and fracture is uneven to conchoidal. Specific gravity is approximately 2.74 to 2.80. Tenacity is brittle.
Optical Properties
Biaxial (-) with refractive indices typically around 1.607 to 1.610. Displays weak pleochroism in shades of purple. Singly or doubly refractive (doubly refractive as a biaxial mineral).
Hardness & Durability
Origin Region
Notable sources include the Chứng Sán mine in South Africa and the Iwagi Islet in Japan. It typically forms in manganese-rich metamorphic environments and alkaline igneous intrusions.
Hardness & Durability
Mohs hardness ranges from 5.5 to 6.5. Moderate toughness, suitable for cabochons and tumbled stones but requires care to avoid scratching against harder stones like quartz.
Care & Maintenance
Clean with warm soapy water and a soft brush. Avoid harsh chemical cleaners, ultrasonic cleaners, and steam cleaning. Store separately in a soft pouch away from prolonged direct sunlight to prevent potential color fading.
Rarity & Value
Rare. High-quality intense purple material with minimal dark matrix is increasingly scarce and commands high prices. No common treatments or enhancements are standard for this material.
Special Characteristics
Known for its rich, hypnotic chatoyant or swirling chatoyant-like patterns in high-grade cabochons, though tumbled specimens primarily feature unique cloud-like color zoning.
Lore & History
Discovered in 1944 by Japanese petrologist Ken-ichi Sugi. In crystal healing lore, sugilite is often called the 'healer's stone' and is associated with the third eye and crown chakras, believed to promote spiritual growth, emotional healing, and wisdom. These are traditional belief systems and not scientifically validated.