Crystopedia
Geode / nodule Healing crystal

Thunderegg

Nodule-like rock, that is formed within rhyolitic volcanic ash layers.

Orange

Thunderegg specimen
Black rock desert thunderegg.JPG · Wikimedia Commons (see file page for author & license)

🪨 Geode facts

AgeCommonly Eocene to Miocene, about 50–15 million years ago. Oregon material is about 30–40 million years old.
Origin & sourcesOregon (state rock: Priday/Richardson's Ranch, Succor Creek), Idaho, Germany, Australia (Mt Hay), Mexico.
CompositionRhyolite or welded-tuff shell with a star-shaped core of agate, chalcedony, jasper or opal

How it forms

Thundereggs form in rhyolitic volcanic ash flows. Gas or shrinkage creates star-shaped cavities that later fill with silica, so they are usually solid (a nodule) rather than hollow.

🌍 Where it's found

  • Type locality
  • Notable source / deposit
  • Country of origin

Marker positions are approximate (region or locality level). Type localities from Wikidata; notable sources curated by Crystopedia.

✨ Metaphysical & Folklore

These are traditional and folk beliefs from crystal lore. They are not scientific or medical claims – crystals are not a substitute for professional care.

Volcanic nodules with star-shaped agate cores, named in Native American legend as eggs hurled by thunder spirits; linked to inner strength.

Traditional uses
inner strength, grounding, creativity
Chakra
Root Sacral
Zodiac
Aries
Element
Earth, Fire

💞 Pairs well with (traditional pairings)

HematiteA natural partner for grounding; Hematite also adds focus. Red JasperPaired in tradition for grounding, with Red Jasper bringing stamina as well. Snowflake ObsidianBoth carry the theme of grounding, so together they're thought to reinforce it. Black TourmalineA natural partner for grounding; Black Tourmaline also adds protection. Clear QuartzLifts and clarifies thunderegg's grounding energy; clear quartz is said to amplify any stone.

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