Definition of "basalt" [ba•salt]

• A hard, dense, dark volcanic rock composed chiefly of plagioclase, pyroxene, and olivine, and often having a glassy appearance. (noun)
• A kind of hard unglazed pottery. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Natural rock pools in basalt rock, 5 km. west of Mecatan."
• "Curious varnished and painted vases, idols in basalt and skeletons were in it."
• "The sand on Mars is from basalt, which is a darkish gray color."