Quartz Geode / Iron-Stained Quartz Matrix
Quartz var. Ferruginous Quartz · Mineral Specimen
Crystal System
Trigonal, massive to crystalline habit with vugs and hollow cavities
Mineral Group
Silicates - Tectosilicates
Chemical Formula
SiO2 with iron oxide/hydroxide (limonite/hematite) surface staining
Formation Process
Hydrothermal and secondary weathering processes where silica-rich fluids deposit quartz within cavities, followed by iron-rich groundwater staining
About This Crystal
A large, weathered boulder showing milky white quartz matrix heavily stained with brown, yellow, and orange iron oxides. Distinct hollow cavities (vugs) are visible on the left side, containing small crystallized quartz points inside.
Physical Characteristics
Color ranges from milky white to golden yellow and deep brown; streak is white; no distinct cleavage; fracture is conchoidal to uneven; specific gravity around 2.65; brittle tenacity
Optical Properties
Uniaxial positive, refractive index of 1.544-1.553, birefringence of 0.009, vitreous to dull luster depending on crystal face and weathering
Hardness & Durability
Origin Region
Worldwide distribution; commonly found in weathering environments, hydrothermal veins, and volcanic host rocks
Hardness & Durability
Mohs hardness of 7; good durability for display, though iron staining can be softer and prone to scratching
Care & Maintenance
Wash with warm soapy water and a soft brush; avoid harsh acids if preserving iron oxide crusts; store away from softer minerals
Rarity & Value
Very common mineral specimen; value depends heavily on size, aesthetics of the vug openings, and crystal formation inside
Special Characteristics
Features iron-stained matrix with hollow vug cavities showing early-stage quartz crystal growth inside
Lore & History
Quartz is traditionally associated with clarity, amplification of energy, and cleansing; used across diverse ancient cultures for tools, ornaments, and spiritual rituals