sedimentary

Hag Stone

Perforated Flint or Chert

Hardness: 6.5-7 (Mohs scale); Color: Gray, tan, or brown with earthy luster; Structure: Cryptocrystalline quartz; Features: A natural hole passing all the way through the stone.

Hardness: 6
Color: Gray, tan, or brown with earthy luster

Identified July 15, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 (Mohs scale); Color: Gray, tan, or brown with earthy luster; Structure: Cryptocrystalline quartz; Features: A natural hole passing all the way through the stone.

Formation & geological history

Formed through thousands of years of water erosion in riverbeds or coastal environments. The holes are often created when a softer part of the rock (like a fossil inclusion or a softer mineral pocket) is worn away by water and abrasive sand.

Uses & applications

Primarily used as lucky charms, protective amulets, or in jewelry. Historically used to ward off 'nightmares' or the 'evil eye'.

Geological facts

Also known as 'Odin stones', 'Adder stones', or 'Witch stones'. Folklore suggests that if you look through the hole, you can see into the 'invisible world' or spot fairies and spirits.

Field identification & locations

Identify by looking for a naturally occurring hole (not drilled) in a water-beaten stone, typically found on pebbly beaches or in ancient river beds. Common in the UK (Dorset coast) and various northern European shores.