mineral
Quartz / Agate Nodule
Silicon Dioxide (SiO2)
Hardness of 7 on the Mohs scale, vitreous to waxy luster, conchoidal fracture, white to clear color with yellowish-brown iron oxide staining on the outer crust, trigonal crystal system, specific gravity of 2.65.
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Physical properties
Hardness of 7 on the Mohs scale, vitreous to waxy luster, conchoidal fracture, white to clear color with yellowish-brown iron oxide staining on the outer crust, trigonal crystal system, specific gravity of 2.65.
Formation & geological history
Formed through the deposition of silica from groundwater solutions in cavities or fractures of host rocks, typically over millions of years in sedimentary or volcanic environments.
Uses & applications
Used in lapidary arts, ornamental carvings, crystal collecting, and occasionally in industrial applications due to its piezoelectric properties.
Geological facts
Quartz is the second most abundant mineral in Earth's continental crust. Specimens featuring small crystal-lined cavities like this are often referred to as geodes or vugs.
Field identification & locations
Easily identified by its high hardness (scratches glass) and conchoidal fracture. Commonly found in riverbeds, gravel deposits, and weathering-resistant outcrops worldwide.
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Potassium Feldspar (Orthoclase)
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