metamorphic
Yellow-brown quartz-rich pebble (possibly iron-stained chert or quartzite)
Quartz (SiO₂), likely with iron-oxide staining; exact identification requires hardness and acid tests
AI-generated identification · may be incorrectMassive, fine-grained, dull to slightly vitreous surface; yellow-brown coloration is likely from limonite/goethite. Quartz hardness is 7, with no cleavage and conchoidal to uneven fracture; specific gravity about 2.65.
Identified More metamorphic →
Explore Yellow-brown quartz-rich pebble (possibly iron-stained chert or quartzite) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Massive, fine-grained, dull to slightly vitreous surface; yellow-brown coloration is likely from limonite/goethite. Quartz hardness is 7, with no cleavage and conchoidal to uneven fracture; specific gravity about 2.65.
Formation & geological history
Probably a naturally weathered silica-rich pebble formed from sedimentary chert or metamorphosed quartz sandstone, later stained by oxidized iron. Precise age and formation environment cannot be determined from the photograph.
Uses & applications
Suitable mainly as a curiosity, lapidary rough, or polished stone; iron-stained quartz-rich material has limited commercial value and is not typically used structurally.
Geological facts
The specimen may scratch ordinary glass if predominantly quartz. A streak test, magnification, and examination of grain texture would help distinguish chert from quartzite.
Field identification & locations
Common in stream gravels and weathered outcrops worldwide. Test whether it scratches glass, inspect for visible interlocking grains, and apply dilute hydrochloric acid only if carbonate minerals are suspected.
More like this
