sedimentary
Hag Stone
Perforated Chert (Microcrystalline Silica, SiO2)
Hardness: 6.5-7 (Mohs scale); Color: Tan, brown, or grey; Luster: Dull to waxy; Texture: Smooth, water-worn with natural cylindrical perforations; Cleavage: None (conchoidal fracture).
- Hardness
- 6
- Color
- Tan, brown, or grey
- Luster
- Dull to waxy
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Physical properties
Hardness: 6.5-7 (Mohs scale); Color: Tan, brown, or grey; Luster: Dull to waxy; Texture: Smooth, water-worn with natural cylindrical perforations; Cleavage: None (conchoidal fracture).
Formation & geological history
Formed through the slow erosion of softer inclusions (like calcite or fossil fragments) or the boring action of marine organisms like Piddock clams (Pholadidae) into harder host rock over thousands of years.
Uses & applications
Primarily used as folk charms, decorative items, garden ornaments, and in holistic jewelry.
Geological facts
In European folklore, hag stones (also called Adder Stones) were believed to protect against witchcraft, bad dreams, and the 'Evil Eye.' It was said that looking through the hole would allow one to see into the fairy realm.
Field identification & locations
Identified by the presence of a naturally formed hole that traverses the entire stone. Commonly found on pebble beaches or in riverbeds under conditions of constant water movement.
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