Moss Agate
Chalcedony (var. Moss Agate) · Semi-Precious Gemstone / Decorative Stone
Crystal System
Trigonal/Hexagonal; typically occurs as microcrystalline aggregates with a massive or botryoidal habit.
Mineral Group
Silicates (Tectosilicate), a variety of Chalcedony which is a cryptocrystalline form of Quartz.
Chemical Formula
SiO2 (Silicon Dioxide) with dendritic inclusions of hornblende or chlorite (iron and manganese oxides).
Formation Process
Hydrothermal/Sedimentary; forms in voids of volcanic rocks where silica-rich fluids deposit layers, with mineral inclusions forming dendritic patterns.
About This Crystal
Translucent to semi-opaque white or colorless chalcedony containing green, organic-looking dendritic inclusions. Vitreous to waxy luster. This specimen is carved into an angel, showing druzy quartz pockets in the lower center.
Physical Characteristics
Color: White/clear base with dark green inclusions; Streak: White; Cleavage: None; Fracture: Conchoidal; Specific Gravity: 2.58-2.64; Fluorescence: Variable, sometimes inert or faint green.
Optical Properties
Refractive Index: 1.544-1.553; Birefringence: Weak (up to 0.009); Pleochroism: None; Optical character: Aggregate; Phenomena: Dendritic pattern visibility.
Hardness & Durability
Origin Region
Notable sources include India, Brazil, Uruguay, USA (Montana), and Central Europe. Found in weathered volcanic rocks and hydrothermal veins.
Hardness & Durability
Mohs hardness 6.5 to 7. Toughness is excellent due to its cryptocrystalline structure. Stable for daily wear and decorative use.
Care & Maintenance
Clean with warm soapy water and a soft brush. Avoid ultrasonic cleaners if druzy pockets are present. Store away from harder stones like sapphires.
Rarity & Value
Common; value is determined by the complexity of the 'moss' patterns, transparency of the host stone, and quality of the carving. Generally affordable.
Special Characteristics
Dendritic inclusions resembling plants, moss, or trees. Small vugs may contain micro-crystalline druzy quartz as seen in this specific carving.
Lore & History
Historically known as a stone of agriculture and gardener's luck. Traditionally associated with the Heart Chakra and believed to promote Emotional Balance and connection to nature.