©FYNDLAY.
Erth2404 - Engineering Geoscience Lab
Practical Exam Study Guide.
Phaneritic - Ans✔✔coarse-grained, crystals are large enough to be seen w/out a microscope,
formed by slow cooling (intrusive)
Pegmatitic - Ans✔✔Very large crystals formed by extremely slow cooling. Rich in volatiles.
Aphanitic - Ans✔✔Rapid cooling at earth's surface results in tiny mineral crystals that can only
be seen under a microscope. Micro-crystals.
Porphyritic - Ans✔✔Type of texture where there are two distinct sizes of crystals in the rock.
Vesicular - Ans✔✔A texture found in extrusive igneous rocks where there are many spherical or
ovoid holes or vesicles present in the rock.
Glassy - Ans✔✔crystal unable to form; Rapid rate of cooling prevents crystals from forming
(e.g. Obsidian)
Pyroclastic - Ans✔✔A special category of volcanic rocks. Formed from the expulsion of ash,
cinders, bombs, and gases during an explosive volcanic eruption.
Mafic - Ans✔✔Igneous Rock containing large amounts of Iron and Magnesium, dark in color
Felsic - Ans✔✔Describes magma or igneous rock that is rich in feldspars and silica and that is
generally light in color.
Sedimentary rock - Ans✔✔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 - Ans✔✔A type of rock that forms from the cooling of molten rock at or below the
surface
Metamorphic - Ans✔✔A type of rock that forms from an existing rock that is changed by heat,
pressure, or chemical reactions.
Organic Sedimentary Rock - Ans✔✔Sedimentary rock (such as coal) formed from carbon-rich
relicts of organisms.
Chert/Flint - Ans✔✔An impure sedimentary rock, often gray, that consists primarily of
extremely small quartz (Silica) crystals precipitated from watery solutions.
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, ©FYNDLAY.
Carbonate - Ans✔✔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 - Ans✔✔A sedimentary rock composed of weathered fragments of older rock.
Evaporites - Ans✔✔sedimentary rocks formed from minerals left after water evaporates
Lithic Fragments - Ans✔✔Sedimentary rocks that contain fragments of rocks and/or minerals as
coarse clastic material (gravel or sand-sized particles e.g. Conglomerates)
Feldspar - Ans✔✔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 - Ans✔✔Protolith is shale or mudrock, contains abundant aluminum.
Quartzo-feldspathic - Ans✔✔If the protolith is a felsic igneous rock that contains abundant
feldspar and quartz.
Calcerous - Ans✔✔If the protolith is a carbonate sedimentary rock (e.g. calcite, dolostone)
Slaty - Ans✔✔Describing a rock that splits easily along nearly flat and parallel planes.
Phyllitic - Ans✔✔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 - Ans✔✔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 - Ans✔✔Coarsely foliated texture in which the minerals have been segregated into
compositional layers or bands.
Olivine - Ans✔✔Green color
Non-metallic lustre - vitreous
6.5-7 hardness (harder than the plate)
Streak is colourless
Cleavage: indistinct
Fracture: semi-conchoidal, uneven
Pyroxene - Ans✔✔Black color
Non-metallic lustre
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Erth2404 - Engineering Geoscience Lab
Practical Exam Study Guide.
Phaneritic - Ans✔✔coarse-grained, crystals are large enough to be seen w/out a microscope,
formed by slow cooling (intrusive)
Pegmatitic - Ans✔✔Very large crystals formed by extremely slow cooling. Rich in volatiles.
Aphanitic - Ans✔✔Rapid cooling at earth's surface results in tiny mineral crystals that can only
be seen under a microscope. Micro-crystals.
Porphyritic - Ans✔✔Type of texture where there are two distinct sizes of crystals in the rock.
Vesicular - Ans✔✔A texture found in extrusive igneous rocks where there are many spherical or
ovoid holes or vesicles present in the rock.
Glassy - Ans✔✔crystal unable to form; Rapid rate of cooling prevents crystals from forming
(e.g. Obsidian)
Pyroclastic - Ans✔✔A special category of volcanic rocks. Formed from the expulsion of ash,
cinders, bombs, and gases during an explosive volcanic eruption.
Mafic - Ans✔✔Igneous Rock containing large amounts of Iron and Magnesium, dark in color
Felsic - Ans✔✔Describes magma or igneous rock that is rich in feldspars and silica and that is
generally light in color.
Sedimentary rock - Ans✔✔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 - Ans✔✔A type of rock that forms from the cooling of molten rock at or below the
surface
Metamorphic - Ans✔✔A type of rock that forms from an existing rock that is changed by heat,
pressure, or chemical reactions.
Organic Sedimentary Rock - Ans✔✔Sedimentary rock (such as coal) formed from carbon-rich
relicts of organisms.
Chert/Flint - Ans✔✔An impure sedimentary rock, often gray, that consists primarily of
extremely small quartz (Silica) crystals precipitated from watery solutions.
1
, ©FYNDLAY.
Carbonate - Ans✔✔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 - Ans✔✔A sedimentary rock composed of weathered fragments of older rock.
Evaporites - Ans✔✔sedimentary rocks formed from minerals left after water evaporates
Lithic Fragments - Ans✔✔Sedimentary rocks that contain fragments of rocks and/or minerals as
coarse clastic material (gravel or sand-sized particles e.g. Conglomerates)
Feldspar - Ans✔✔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 - Ans✔✔Protolith is shale or mudrock, contains abundant aluminum.
Quartzo-feldspathic - Ans✔✔If the protolith is a felsic igneous rock that contains abundant
feldspar and quartz.
Calcerous - Ans✔✔If the protolith is a carbonate sedimentary rock (e.g. calcite, dolostone)
Slaty - Ans✔✔Describing a rock that splits easily along nearly flat and parallel planes.
Phyllitic - Ans✔✔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 - Ans✔✔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 - Ans✔✔Coarsely foliated texture in which the minerals have been segregated into
compositional layers or bands.
Olivine - Ans✔✔Green color
Non-metallic lustre - vitreous
6.5-7 hardness (harder than the plate)
Streak is colourless
Cleavage: indistinct
Fracture: semi-conchoidal, uneven
Pyroxene - Ans✔✔Black color
Non-metallic lustre
2
