sedimentary
Hag Stone
Siltstone or Fine-grained Sandstone with boring (e.g., Lithophaga impact)
Hardness: 6-7 (Mohs); Color: Grey to brownish-grey; Luster: Dull/Earthy; Structure: Granular sedimentary matrix; Features smooth, circular holes bored through the stone.
- Hardness
- 6-7 (Mohs)
- Color
- Grey to brownish-grey
- Luster
- Dull/Earthy
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Physical properties
Hardness: 6-7 (Mohs); Color: Grey to brownish-grey; Luster: Dull/Earthy; Structure: Granular sedimentary matrix; Features smooth, circular holes bored through the stone.
Formation & geological history
Formed through the accumulation of fine sediments over millions of years. The distinctive holes are typically created by the boring action of piddock clams or other marine organisms, combined with wave erosion in coastal environments.
Uses & applications
Primarily used as a curiosity, talisman, or decorative garden piece. Historically used in folklore for protection or 'seeing' into invisible realms.
Geological facts
Also known as Odin stones, adder stones, or fairy stones. Folklore suggests that looking through the hole allows one to see woodland spirits or fairies, and they were often hung over stable doors to protect livestock.
Field identification & locations
Identify by looking for natural, smooth-edged holes in a water-worn sedimentary rock. Common in coastal areas of the UK and Northeastern US. Collectors value them for the number and placement of naturally occurring holes.
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