from The American Heritage® Dictionary of the English Language, 5th Edition.
- adjective Having right-angled cleavage.
from The Century Dictionary.
- Characterized by cleavages at right angles to one another: said of certain species of the feldspar group, particularly orthoclase; pertaining to such species, or specifically to orthoclase.
from the GNU version of the Collaborative International Dictionary of English.
- adjective (Crystallog.) Breaking in directions at right angles to each other; -- said of the monoclinic feldspars.
from Wiktionary, Creative Commons Attribution/Share-Alike License.
- adjective crystallography Having
cleavage planesat right angles; as in orthoclase.
from Wiktionary, Creative Commons Attribution/Share-Alike License
ortho- + Ancient Greek κλαστός (klastos, "broken") + -ic
Both plagioclastic and orthoclastic aventurine occur at several localities in the United States.