sedimentary
Hag Stone
Perforated Flint or Chert (SiO2)
AI-generated identification · may be incorrectHardness: 6.5-7 (Mohs); Color: Tan, grey, or brownish; Luster: Waxy to dull; Structure: Cryptocrystalline; Features: Natural through-hole caused by erosion.
- Hardness
- 6
- Color
- Tan, grey, or brownish
- Luster
- Waxy to dull
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Physical properties
Hardness: 6.5-7 (Mohs); Color: Tan, grey, or brownish; Luster: Waxy to dull; Structure: Cryptocrystalline; Features: Natural through-hole caused by erosion.
Formation & geological history
Formed as nodules in limestone or chalk beds during the Cretaceous period. The holes are created over thousands of years by the abrasive action of water, sand, or sponges/mollusks boring into softer inclusions.
Uses & applications
Primarily used as a protective talisman in folklore, or in modern jewelry and home decor. Historically used to ward off 'nightmares' or the 'evil eye'.
Geological facts
Also known as Adder Stones, Witch Stones, or Odin Stones. In many cultures, looking through the hole is said to reveal the 'invisible' or faerie realm.
Field identification & locations
Identify by finding a rock with a naturally occurring hole that goes all the way through. Most commonly found on beaches or in riverbeds where water erosion is high.
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