sedimentary
Hag Stone (Holey Rock / Fossiliferous Limestone)
Limestone (CaCO3) with natural erosion / fossil cavities
Hardness: 3 on Mohs scale (calcite matrix). Color: Light grey to brownish-white. Luster: Dull, earthy. Structure: Non-crystalline, fine-grained clastic/biogenic matrix. Features prominent naturally eroded holes through the body.
- Hardness
- 3 on Mohs scale (calcite matrix)
- Color
- Light grey to brownish-white
- Luster
- Dull, earthy
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Physical properties
Hardness: 3 on Mohs scale (calcite matrix). Color: Light grey to brownish-white. Luster: Dull, earthy. Structure: Non-crystalline, fine-grained clastic/biogenic matrix. Features prominent naturally eroded holes through the body.
Formation & geological history
Formed in shallow marine environments from accumulated calcium carbonate sediment and fossil remains. The distinctive holes are created over time by wave action, water erosion, or burrowing organisms like piddock clams.
Uses & applications
Historically used as protective talismans and folk amulets. Popular among collectors, beachcombers, and crafters for jewelry, wind chimes, and decorative items.
Geological facts
Hag stones, also known as adder stones, witch stones, or holey stones, have rich folklore across Northern Europe. Traditionally, looking through the hole was believed to allow one to see fairies, spirits, or see through illusions and witches' magic.
Field identification & locations
Identified by natural, smooth-edged holes passing entirely or partially through rounded beach pebbles or river rocks. Commonly found along marine beaches, rocky coasts, and riverbeds in limestone-rich regions.
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