A name formerly applied rather loosely to certain dark-colored igneous rocks, including diorite, diabase, etc.
An old field name for compact, igneous rocks which have developed enough chlorite in alteration to give them a greenish color. If the rock is finely foliated, it is called greenstone schist.
A field term for any compact dark green altered or metamorphosed basic igneous rock that owes its colour to chlorite.
A low-grade metamorphic rock that frequently contains green minerals such as chlorite, epidote and talc.
A low-grade metamorphic rock that commonly has green minerals such as chlorite and talc.
a field term applied to any compact dark-green altered or metamorphosed basic igneous rock that owes its color to the presence of chlorite, actinolite or epidote. to top
a field term for altered basic igneous rocks
Green to gray-green, fine- to coarse-grained, massive to poorly layered metamorphic rock composed of chlorite, hornblende, and epidote.
A field term applied to any low-grade metamorphosed mafic igneous rock (for example, basalt, gabbro, or diabase). Chlorite accounts for their greenish cast.
Stones that have been metamorphosed or otherwise so altered that they have assumed a distinctive greenish color owing to the presence of one or more of the following minerals: chlorite, epidote, or actinolite.
(1) A vague name for any compost basic or intermediate igneous rock. (Chambers, 550) (2) A wide term, usually comprising the greenish-coloured eruptive rocks containing feldspar and hornblende (or augite), such as diorite, melaphyre, etc. [also nephrite] Oxford, 888.
metamorphic rock derived from basalt or chemically equivalent rock such as gabbro. Greenstones contain sodium-rich plagioclase feldspar, chlorite, and epidote, as well as quartz. The chlorite and epidote make greenstones green.
basalt subjected to low temperature- and pressure-metamorphism. The resulting rock has a greenish-black color due to the presence of chlorite (a dark green mica) and epidote (a yellowish-green mineral) which developed during metamorphism.
a metamorphic (cooked) rock whose green colour is due to the presence of chlorite, epidote or actinolite. Commonly a loose term used to describe deformed, recrystallized volcanic and/or sedimentary rock which has a high amphibole content as a result of its original bulk composition
Volcanic rock, such as an andesite or basalt, that has been metamorphosed by high temperature and pressure.
a metamorphosed volcanic rock in which green minerals impart the color
Greenstone is another name for nephrite, a semi-precious stone and a variety of jade. Nephrite is slightly softer that jadeite and is often veined; it is used in carvings, for making beautiful bowls and vases.
metamorphosed mafic igneous rock which is typically green due to content of chlorite, actinolite, etc.
A basaltic lava with a grey-green to yellow-green coloring derived from the presence of the mineral Chlorite. A metamorphic rock, it indicates volcanic origin followed by periods of intense heat and pressure. This rock was probably buried deep and later exposed by erosion. Occurs in belts running more or less NE/SW and includes the Ely Greenstone formation, which crops up in the town of Ely. Pillow structure in Ely Greenstone suggests lava which hardened underwater. Supports Island Arc Theory of Origin.
A type of nephrite jade known in Maori as pounamu.