The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.
igneous rock in which the quantity of light-colored minerals (feldspars, quartz, and feldspathoids) is greater than in the normal average type of rock. Leucocratic rock is contrasted with melanocratic rock.
The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.