Erth2404 - Engineering Geoscience Lab
Practical Test With Complete Solution
Phaneritic - ANSWER coarse-grained, crystals are large enough to be seen
w/out a microscope, formed by slow cooling (intrusive)
Pegmatitic - ANSWER Very large crystals formed by extremely slow cooling.
Rich in volatiles.
Aphanitic - ANSWER Rapid cooling at earth's surface results in tiny mineral
crystals that can only be seen under a microscope. Micro-crystals.
Porphyritic - ANSWER Type of texture where there are two distinct sizes of
crystals in the rock.
Vesicular - ANSWER A texture found in extrusive igneous rocks where there
are many spherical or ovoid holes or vesicles present in the rock.
Glassy - ANSWER crystal unable to form; Rapid rate of cooling prevents
crystals from forming (e.g. Obsidian)
Pyroclastic - ANSWER A special category of volcanic rocks. Formed from the
expulsion of ash, cinders, bombs, and gases during an explosive volcanic
eruption.
Mafic - ANSWER Igneous Rock containing large amounts of Iron and
Magnesium, dark in color
Felsic - ANSWER Describes magma or igneous rock that is rich in feldspars
and silica and that is generally light in color.
Sedimentary rock - ANSWER A type of rock that forms when particles from
,other rocks or the remains of plants and animals are pressed and cemented
together
Igneous rock - ANSWER A type of rock that forms from the cooling of molten
rock at or below the surface
Metamorphic - ANSWER A type of rock that forms from an existing rock that
is changed by heat, pressure, or chemical reactions.
Organic Sedimentary Rock - ANSWER Sedimentary rock (such as coal) formed
from carbon-rich relicts of organisms.
Chert/Flint - ANSWER An impure sedimentary rock, often gray, that consists
primarily of extremely small quartz (Silica) crystals precipitated from watery
solutions.
Carbonate - ANSWER Is a common mineral that occurs as the major
constituent of limestone or as the cementing material in clastic rocks. (Calcite
CaCO3) a weak reaction will occur if you scratch the rock and apply HCl.
Clastic - ANSWER A sedimentary rock composed of weathered fragments of
older rock.
Evaporites - ANSWER sedimentary rocks formed from minerals left after
water evaporates
Lithic Fragments - ANSWER Sedimentary rocks that contain fragments of
rocks and/or minerals as coarse clastic material (gravel or sand-sized
particles e.g. Conglomerates)
Feldspar - ANSWER In some circumstances, sedimentary rocks may often
contain significant amounts of feldspar. Feldspar often break down into clay
minerals during weathering. (e.g. plagioclase and orthoclase)
, Aluminous - ANSWER Protolith is shale or mudrock, contains abundant
aluminum.
Quartzo-feldspathic - ANSWER If the protolith is a felsic igneous rock that
contains abundant feldspar and quartz.
Calcerous - ANSWER If the protolith is a carbonate sedimentary rock (e.g.
calcite, dolostone)
Slaty - ANSWER Describing a rock that splits easily along nearly flat and
parallel planes.
Phyllitic - ANSWER refers to the alignment of platy (sheet-like) minerals into
a layered structure, where the minerals are too small to recognize. Biggest
distinction between phyllite and schist is usually crystal size.
Schistose - ANSWER The texture of a rock in which visible platy or
needle-shaped minerals have grown essentially parallel to each other under
the influence of directed pressure. Have a shiny metallic appearance.
Gniessic - ANSWER Coarsely foliated texture in which the minerals have been
segregated into compositional layers or bands.
Olivine - ANSWER Green color
Non-metallic lustre - vitreous
6.5-7 hardness (harder than the plate)
Streak is colourless
Cleavage: indistinct
Fracture: semi-conchoidal, uneven
Practical Test With Complete Solution
Phaneritic - ANSWER coarse-grained, crystals are large enough to be seen
w/out a microscope, formed by slow cooling (intrusive)
Pegmatitic - ANSWER Very large crystals formed by extremely slow cooling.
Rich in volatiles.
Aphanitic - ANSWER Rapid cooling at earth's surface results in tiny mineral
crystals that can only be seen under a microscope. Micro-crystals.
Porphyritic - ANSWER Type of texture where there are two distinct sizes of
crystals in the rock.
Vesicular - ANSWER A texture found in extrusive igneous rocks where there
are many spherical or ovoid holes or vesicles present in the rock.
Glassy - ANSWER crystal unable to form; Rapid rate of cooling prevents
crystals from forming (e.g. Obsidian)
Pyroclastic - ANSWER A special category of volcanic rocks. Formed from the
expulsion of ash, cinders, bombs, and gases during an explosive volcanic
eruption.
Mafic - ANSWER Igneous Rock containing large amounts of Iron and
Magnesium, dark in color
Felsic - ANSWER Describes magma or igneous rock that is rich in feldspars
and silica and that is generally light in color.
Sedimentary rock - ANSWER A type of rock that forms when particles from
,other rocks or the remains of plants and animals are pressed and cemented
together
Igneous rock - ANSWER A type of rock that forms from the cooling of molten
rock at or below the surface
Metamorphic - ANSWER A type of rock that forms from an existing rock that
is changed by heat, pressure, or chemical reactions.
Organic Sedimentary Rock - ANSWER Sedimentary rock (such as coal) formed
from carbon-rich relicts of organisms.
Chert/Flint - ANSWER An impure sedimentary rock, often gray, that consists
primarily of extremely small quartz (Silica) crystals precipitated from watery
solutions.
Carbonate - ANSWER Is a common mineral that occurs as the major
constituent of limestone or as the cementing material in clastic rocks. (Calcite
CaCO3) a weak reaction will occur if you scratch the rock and apply HCl.
Clastic - ANSWER A sedimentary rock composed of weathered fragments of
older rock.
Evaporites - ANSWER sedimentary rocks formed from minerals left after
water evaporates
Lithic Fragments - ANSWER Sedimentary rocks that contain fragments of
rocks and/or minerals as coarse clastic material (gravel or sand-sized
particles e.g. Conglomerates)
Feldspar - ANSWER In some circumstances, sedimentary rocks may often
contain significant amounts of feldspar. Feldspar often break down into clay
minerals during weathering. (e.g. plagioclase and orthoclase)
, Aluminous - ANSWER Protolith is shale or mudrock, contains abundant
aluminum.
Quartzo-feldspathic - ANSWER If the protolith is a felsic igneous rock that
contains abundant feldspar and quartz.
Calcerous - ANSWER If the protolith is a carbonate sedimentary rock (e.g.
calcite, dolostone)
Slaty - ANSWER Describing a rock that splits easily along nearly flat and
parallel planes.
Phyllitic - ANSWER refers to the alignment of platy (sheet-like) minerals into
a layered structure, where the minerals are too small to recognize. Biggest
distinction between phyllite and schist is usually crystal size.
Schistose - ANSWER The texture of a rock in which visible platy or
needle-shaped minerals have grown essentially parallel to each other under
the influence of directed pressure. Have a shiny metallic appearance.
Gniessic - ANSWER Coarsely foliated texture in which the minerals have been
segregated into compositional layers or bands.
Olivine - ANSWER Green color
Non-metallic lustre - vitreous
6.5-7 hardness (harder than the plate)
Streak is colourless
Cleavage: indistinct
Fracture: semi-conchoidal, uneven
