metamorphic
Rounded quartz-veined pebble
Likely quartz-veined metamorphic rock; exact host rock is indeterminate from the image
AI-generated identification · may be incorrectDark gray-brown, fine-grained, subrounded and water-worn, with pale quartz-rich veins and a dull to weakly satin luster. Likely hardness about 6–7 where quartz is exposed; cleavage is absent, and specific gravity is approximately 2.6–2.8.
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Physical properties
Dark gray-brown, fine-grained, subrounded and water-worn, with pale quartz-rich veins and a dull to weakly satin luster. Likely hardness about 6–7 where quartz is exposed; cleavage is absent, and specific gravity is approximately 2.6–2.8.
Formation & geological history
Probably a stream- or beach-rounded fragment of metamorphosed silicate rock cut by later quartz veins. The host rock may be slate, phyllite, or fine-grained volcanic rock; its geological age cannot be determined visually.
Uses & applications
Primarily a collecting or lapidary specimen; it may be polished as an attractive pebble but has no significant commercial use in this small form.
Geological facts
The contrasting pale bands are likely quartz filling fractures, while the dark matrix may contain mica, chlorite, or iron-bearing minerals. A streak, acid, hardness, and thin-section test would improve identification.
Field identification & locations
Common in regions with metamorphic or hydrothermal rocks and quartz-bearing veins. Look for glassy quartz grains, no reaction to dilute hydrochloric acid, and quartz scratching ordinary steel or glass.
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