Earth & SkyGreek → English
Geode
/ˈdʒiːoʊd/noun
A hollow rock whose inner cavity is lined with crystals.
The Greek roots
γῆ
gê
earth
εἶδος
eîdos
form, likeness
Literally: “earth-like”
The story of the word
Pliny lists geodes among stones that rattle, calling it the earthy one because it seemed to hold loose ground inside. That is nearly right: a gas bubble in lava or a cavity in limestone fills slowly with mineral-laden water, and the crystals grow inward over a very long time. Nothing on the dull outside tells you whether the inside is grey quartz or amethyst, which is why the sellers at rock fairs charge before cutting.
- How it travelled
- Ancient Greek → Latin → English
- First recorded
- 17th century
Same family
geologygeographygeodesygeothermal
In a sentence
He split the geode with a chisel and found a cave of purple points.