|
OBSIDIAN |
Igneous rock |
|
NORITE |
Igneous rock |
|
DIABASE |
Igneous rock |
|
DIORITE |
Igneous rock |
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BASALT |
Igneous rock |
|
GRANITE |
Igneous rock |
|
LAVA |
Igneous volcanic rock |
|
ANDESITE |
Igneous volcanic rock |
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DITROITE |
An igneous rock composed of orthoclase, elaeolite, and
sodalite. |
|
RHYOLITE |
A quartzose trachyte, an igneous rock often showing a
fluidal structure. |
|
PITCHSTONE |
An igneous rock of semiglassy nature, having a luster
like pitch. |
|
PICRITE |
A dark green igneous rock, consisting largely of
chrysolite, with hornblende, augite, biotite, etc. |
|
TEPHRITE |
An igneous rock consisting essentially of plagioclase and
either leucite or nephelite, or both. |
|
CLINKSTONE |
An igneous rock of feldspathic composition, lamellar in
structure, and clinking under the hammer. See Phonolite. |
|
LHERZOLITE |
An igneous rock consisting largely of chrysolite, with
pyroxene and picotite (a variety of spinel containing chromium). |
|
LACCOLITH |
A mass of igneous rock intruded between sedimentary beds
and resulting in a mammiform bulging of the overlying strata. |
|
PHONOLITE |
A compact, feldspathic, igneous rock containing
nephelite, hauynite, etc. Thin slabs give a ringing sound when struck;
-- called also clinkstone. |
|
TRACHYTE |
An igneous rock, usually light gray in color and breaking
with a rough surface. It consists chiefly of orthoclase feldspar with
sometimes hornblende and mica. |
|
DOLERITE |
A dark-colored, basic, igneous rock, composed essentially
of pyroxene and a triclinic feldspar with magnetic iron. By many
authors it is considered equivalent to a coarse-grained basalt. |
|
TRAP |
An old term rather loosely used to designate various
dark-colored, heavy igneous rocks, including especially the
feldspathic-augitic rocks, bas... |
|
GABBRO |
... of
serpentine, later to the rock called euphotide, and now generally used
for a coarsely crystalline, igneous rock consisting of lamellar
py... |