geode

American  

[jee-ohd] / ˈdʒi oʊd /

noun

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

2. the hollow or cavity of this.

3. any similar formation.

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geode British  

/ dʒɪˈɒdɪk, ˈdʒiːəʊd /

noun

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

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geode Scientific  

/ jē′ōd′ /

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.

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Other Word Forms

• geodal adjective
• geodic adjective

Etymology

Origin of geode

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

Example Sentences

"It's like a geode. It's ugly on the outside, and the treasure is all inside."

From Science Daily

After pouring hot aluminum into one of her stick-shaped molds and letting it cool in a pile of dirt, a participant took a ball-peen hammer and cracked open the rough silicate mold, like a geode.

From Los Angeles Times

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

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

From Seattle Times

The wooden coffee table in her living room has a massive, cracked geode slice embedded in its center.

From Literature