metamorphic
Rounded quartz-rich pebble, likely quartzite or chert
Quartzite (mostly microcrystalline SiO₂); exact identification requires hardness and acid tests
AI-generated identification · may be incorrectPale gray-green, smooth water-worn surface, dull to subtly waxy luster, massive texture, no visible cleavage; quartz hardness Mohs 7 and specific gravity about 2.65. The image alone cannot distinguish quartzite from fine-grained chert or a weathered quartz pebble.
Identified More metamorphic →
Explore Rounded quartz-rich pebble, likely quartzite or chert in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Pale gray-green, smooth water-worn surface, dull to subtly waxy luster, massive texture, no visible cleavage; quartz hardness Mohs 7 and specific gravity about 2.65. The image alone cannot distinguish quartzite from fine-grained chert or a weathered quartz pebble.
Formation & geological history
Likely formed from silica-rich sandstone metamorphosed into quartzite, or from microcrystalline silica forming chert, then rounded by stream or beach transport; age is indeterminate and may range from Precambrian to recent sedimentary settings.
Uses & applications
Commonly used as aggregate, road stone, landscaping material, and occasionally ornamental stone; this ordinary pebble has little jewelry value.
Geological facts
Quartz-rich rocks resist weathering, producing smooth, durable pebbles. Greenish coloration may reflect chlorite, epidote, or other minor minerals, but color alone is not diagnostic.
Field identification & locations
Common in streambeds, beaches, glacial deposits, and areas underlain by quartzite or chert. It should scratch ordinary glass and resist a steel knife; no fizz with dilute hydrochloric acid supports a silica-rich identification.
More like this
