Rock Identifier
Hag Stone (Odin Stone / Adder Stone) (Perforated Pebble (commonly Chert, Mudstone, or Limestone)) — sedimentary
sedimentary

Hag Stone (Odin Stone / Adder Stone)

Perforated Pebble (commonly Chert, Mudstone, or Limestone)

Hardness varies from 3 to 7 Mohs depending on rock composition, matte earthy brown color, dull to earthy luster, microcrystalline or fine-grained texture, featuring naturally eroded boreholes.

Identified More sedimentary
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Physical properties

Hardness varies from 3 to 7 Mohs depending on rock composition, matte earthy brown color, dull to earthy luster, microcrystalline or fine-grained texture, featuring naturally eroded boreholes.

Formation & geological history

Formed in marine, riverine, or coastal environments where water flow, abrasive sand, or boring organisms (such as piddock clams) erode small holes through soft spots in pebbles over long periods.

Uses & applications

Used historically as protective amulets, folklore talismans to ward off evil spirits or nightmares, and held in curiosity collections.

Geological facts

According to European folklore, looking through the natural hole of a hag stone allows a person to see fairies, witches, or hidden truths.

Field identification & locations

Identify by inspecting the hole to ensure it is naturally eroded by water or biological activity rather than drilled artificially. Commonly found along beaches, riverbeds, and gravel deposits.