greywacke (English, noun)
expansion: greywacke (countable and uncountable, plural greywackes)
Senses:
topics: geography
geology
natural-sciences
glosses: A hard dark sandstone with poorly sorted angular grains of quartz, feldspar, and small rock fragments in a compact, clay-fine matrix.
tags: countable
uncountable
Forms:
form: greywackes
tags: plural
form: graywacke
tags: alternative