diabase
/daɪˈbeɪs/Definitions
1. noun
A dark, fine-grained type of igneous rock, typically having a prismatic or columnar structure, and composed of labradorite or other feldspathic minerals.
“The geologist carefully examined the diabase formation to understand its geological history.”
2. adjective
Relating to or consisting of diabase.
“The diabase rocks were formed as a result of volcanic activity.”