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geode

American  
[jee-ohd] / ˈdʒi oʊd /

noun

geodes plural
  1. a hollow concretionary or nodular stone often lined with crystals.

  2. the hollow or cavity of this.

  3. any similar formation.


geode British  
/ dʒɪˈɒdɪk, ˈdʒiːəʊd /

noun

  1. a cavity, usually lined with crystals, within a rock mass or nodule

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

geode Scientific  
/ jēōd′ /
  1. A small, hollow, usually rounded rock lined on the inside with inward-pointing crystals. Geodes form when mineral-rich water entering a cavity in a rock undergoes a sudden change in pressure or temperature, causing crystals to form from the solution and line the cavity's walls.


Other Word Forms

Derived Forms

Inflected Forms

Nouns

Etymology

Origin of geode

1670–80; < French géode < Latin geōdēs < Greek geṓdēs earthlike. See geo-, -ode 1

Explanation

On the outside, a geode looks like an ordinary rock, but when you break a geode open, it's full of crystals. Geodes are hollow rock formations with minerals, often quartz crystals, massed inside. A geode forms when minerals settle into a hollow in the earth (like an animal burrow) or inside volcanic rock bubbles. First, a hard shell is formed, and then the minerals grow toward the center of the geode, often forming crystals in the process. The Greek root, geodes, means "earth-like."

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Vocabulary lists containing geode

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

Heyward co-hosted a fundraiser with his wife last week where Pratt was smudged with sage before standing in front of a giant amethyst geode to address about 125 people.

From The Wall Street Journal May 21, 2026

Looking like a glittering cosmic geode, a trio of dazzling stars blaze from the hollowed-out cavity of a reflection nebula in this new image from NASA's Hubble Space Telescope.

From Science Daily May 15, 2024

“This place is as good as it gets,” Losson said recently as he hoisted a small geode filled with quartz crystals.

From Los Angeles Times Jul. 16, 2023

After every death, Nadia wakes up back in Maxine's cool bathroom with a glowing geode on the door and a gun-shaped door handle.

From Salon Apr. 16, 2022

The next morning I took the watch out of the wooden box where I kept my geode, put it in my purse, and brought it back to the store.

From "The Glass Castle" by Jeannette Walls

Each Rock Box includes a curated selection of high-quality crystals, rough rock, agates, geodes, gem collectibles and more.

From Seattle Times Nov. 16, 2023

Samples stood on the disused fireplace: carved angels, pyramids, geodes, wands.

From The Guardian Sep. 17, 2019

As a jazzy tune played over a boombox, they passed a few amethyst geodes and approached a large glass case displaying rocks with magnets affixed to them.

From The Verge Jun. 25, 2018

The main heat is built around geodes, a drab rock that doesn't show its inner beauty until cracked open.

From Los Angeles Times Apr. 29, 2018

My favorite rocks to find were geodes, which Monyaid came from the volcanoes that had erupted to form the Tuscarora Mountains millions of years ago, during the Miocene period.

From "The Glass Castle" by Jeannette Walls

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