Spherulites in the Hot Creek rhyolite flow, Long Valley Caldera
![A hand holds a geologic scalebar against the face of an outcrop. The outcrop is a mix of large, pink, circular crystal masses interspersed with black glassy chunks, both several cm in diameter.](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/full_width/public/media/images/DSC_1750.png?itok=Z4beGTnJ)
Detailed Description
Spherulites are distinctive rounded masses of radiating needle-like crystals which form by devitrification, a process where glassy, non-crystalline substances restructure into crystalline ones. USGS photo by Jessica Ball.
Sources/Usage
Public Domain.