sedimentary
Hag Stone
Perforated Sandstone (composed of SiO2 and calcareous cement)
Hardness: 6-7 (Mohs scale), Color: Grey to brownish-grey, Luster: Dull/Earthy, Structure: Fine-grained clastic, Cleavage: None, Specific Gravity: 2.5-2.8
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Physical properties
Hardness: 6-7 (Mohs scale), Color: Grey to brownish-grey, Luster: Dull/Earthy, Structure: Fine-grained clastic, Cleavage: None, Specific Gravity: 2.5-2.8
Formation & geological history
Formed through mechanical erosion by water carrying smaller pebbles or biological erosion by boring mollusks (piddocks). Usually found in coastal or riverbed environments as sedimentary deposits.
Uses & applications
Primarily used as decorative items, lucky charms in folklore, or geological curiosities. In some historical contexts, used as weights for fishing nets.
Geological facts
Also known as Adder Stones, Odin Stones, or Holy Stones. In European folklore, they were believed to protect against witchcraft and were often hung on stable doors to prevent horses from being 'night-ridden'.
Field identification & locations
Identify by a naturally occurring hole that goes all the way through the stone. Commonly found on beaches in the UK, Ireland, and the northeastern US. Check for smoothed edges within the hole to confirm natural water erosion.
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