Basalt

• (anthropology, archaeology) a fine-grained volcanic rock used for the manufacture of chipped stone artifacts. Color black to gray, texture granular to glass-like.
• (environment) Consistent year-round energy use of a facility; also refers to the minimum amount of electricity supplied continually to a facility.
  Source: Terms of the Environment
• (geology)

1. A fine-grained colored extrusive rocks.
   Source: Leet, L. Don. 1982. Physical Geology, 6th Edition. Englewood Cliffs, NJ: Prentice-Hall
2. A general term for dark-colored mafic igneous rocks, commonly extrusive but locally intrusive (e.g., as dikes), composed chiefly of calcic plagioclase and clinopyroxene; the fine-grained equivalent of gabbro. Nepheline, olivine, orthopyroxene, or quartz may be present. Adj. basaltic. CF: tholeiite
   Source: Dictionary of Mining, Mineral, and Related Terms