Any of various altered basic igneous rocks colored green by chlorite, hornblende, or epidote.
Any of various altered basic igneous rocks having a dark-green color.
Any of various green metamorphic rocks formed from igneous rocks that have a relatively low silica content and owe their color to the presence of a green mineral such as chlorite, hornblende, or epidote.
The rocks of its lower half are mainly granite and gneiss; its upper half is composed of porphyritic greenstone, and a variety of minerals occur.
The plain, sandy in its northern part, is in the south a deep bed of argillaceous marl, scattered over with great granite boulders and fragments of greenstone.
by 92, was built of blocks of greenstone and cased with marble.
In every other part the surface is hilly or mammilated, the harder rocks, such as granite or greenstone, rising as rounded knobs, or in the case of schists forming narrow ridges, while the softer parts form valleys generally floored with lakes.
high, "some like gigantic tusks, some like sugar-loaves, and some like vast stalagmites," but all consisting of iron-grey or reddishbrown conglomerate of gneiss, mica-slate, syenite and greenstone.