Hypertext Webster Gateway: "greenstone"
From Webster's Revised Unabridged Dictionary (1913) (web1913)
Greenstone \Green"stone`\ (gr[=e]n"st[=o]n`), n. [So called from
a tinge of green in the color.] (Geol.)
A name formerly applied rather loosely to certain
dark-colored igneous rocks, including diorite, diabase, etc.
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