We observe, for instance, gneiss alternating with layers of black hornblende-schist or of green Chlorite-schist, or with granular quartz or limestone; and the interchange of these different strata may be repeated for an indefinite number of times.
"The Student's Elements of Geology"
Sir Charles Lyell
But if we investigate different mountain chains, we find gneiss, mica-schist, hornblende-schist, Chlorite-schist, hypogene limestone, and other rocks, succeeding each other, and alternating with each other in every possible order.
"The Student's Elements of Geology"
Sir Charles Lyell
Chlorite is another soft, easily scratched mineral, generally of a dark-green colour.
"Geology"
James Geikie