- a crystal that forms in metamorphic rock and gets its outline from neighboring crystals.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
- A mineral that has not developed its characteristic crystalline faces and that has formed in a rock that has undergone metamorphism.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.