from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A dark-gray to black, fine-textured igneous rock composed mainly of feldspar and pyroxene and used for monuments and as crushed stone.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A fine-grained igneous rock composed mostly of pyroxene and feldspar
from the GNU version of the Collaborative International Dictionary of English
- n. A basic, dark-colored, holocrystalline, igneous rock, consisting essentially of a triclinic feldspar and pyroxene with magnetic iron; -- often limited to rocks pretertiary in age. It includes part of what was early called greenstone.
from The Century Dictionary and Cyclopedia
- n. The name originally given by A. Brongniart to a rock which Haüy later designated as diorite, which name Brongniart himself adopted in preference to that of diabase.
The boulders are made of a substance called diabase which is basically volcanic basalt.
On steep ridges, soils derived from basalt or diabase are often unstable; they tend to creep downslope, creating shallow, ledgy soils on upper slopes, and deeper, wetter gley soils on lower slopes near the bases of ridges.
In moister valleys, ravines, and on steep, lower, north-facing diabase ridges, hemlock-mixed hardwood forests are native.
Acid loving plants are absent from diabase and basalt areas.
On diabase and basalt ridge slopes, mixed oak forests are found; red oak, white oak, and black oak are most common, and sugar maple, chestnut oak, black birch, white ash, and tulip tree occur.
Molten diabase and basalt (i.e., “trap rock”) intruded shales, argillites, conglomerates, and reddish sandstones along the scattered sills and dikes of Ecoregion 64b during the Triassic Period.
In New Jersey, native vegetation is mixed oak forest on well-drained upland sites over sandstone, shale, diabase, and basalt.
Stony, non-acidic, fine-textured soils with a heavy clay subsoil are common over diabase; they are hard to till and best suited for forest or pasture.
Stony, steep, mostly wooded ridges, hills, and palisades that are composed of highly resistant diabase, basalt, or heat-altered sedimentary rock.
Partly glaciated, irregular plains and low hills that have been extensively cleared for farms or suburban-urban developments; in addition, large old glacial lake beds are found near the Wisconsinan terminal moraine, and scattered, forested, rocky ridges occur on diabase and basalt intrusions.