Moss Agate
Quartz var. Moss Agate (Chalcedony) · Semi-Precious Gemstone
Crystal System
Trigonal (Hexagonal) - Microcrystalline; massive, nodular, or cryptocrystalline habit
Mineral Group
Silicates (Tectosilicate)
Chemical Formula
SiO2 with inclusions of Ferric Oxide, Hornblende, or Chlorite
Formation Process
Hydrothermal and Sedimentary; forms in voids of volcanic rocks through the deposition of silica
About This Crystal
Translucent to semi-opaque chalcedony containing green, black, or reddish dendritic inclusions that resemble moss or plants. It features a waxy to vitreous luster and a varied mottled appearance.
Physical Characteristics
Color: Milky white to clear base with green/brown inclusions; Streak: White; Cleavage: None; Fracture: Conchoidal; Specific Gravity: 2.58-2.64; Fluorescence: Weak yellow-green under SW UV.
Optical Properties
Refractive Index: 1.530-1.543; Birefringence: Up to 0.004; Optical Sign: Uniaxial (+); Non-pleochroic; typically aggregate structure.
Hardness & Durability
Origin Region
India, Brazil, USA (Montana, Wyoming), Uruguay, and Central Europe
Hardness & Durability
Mohs Hardness: 6.5 to 7; Good toughness with no cleavage; highly stable and suitable for daily jewelry wear.
Care & Maintenance
Clean with warm soapy water and a soft brush; avoid ultrasonic cleaners and harsh chemicals; store away from harder stones like diamonds.
Rarity & Value
Common; value is determined by the complexity and beauty of the dendritic 'moss' patterns rather than carat weight; generally affordable.
Special Characteristics
Dendritic/moss-like inclusions caused by manganese and iron oxides branching during mineral growth; occasionally shows color-zoning.
Lore & History
Historically used as a talisman by agricultural cultures for bountiful harvests; symbolically associated with nature, growth, and the heart chakra in traditional healing practices.