5/1/07
Rocks Essential Knowledge and Skills
This provides a list of Essential Knowledge and Skills that the student must master in
order to be successful taking the Virginia SOL Test that will be administered at the end of
the course.
The student should check off each line item as their knowledge level is achieved. If at ANY
TIME the student is having difficulty understanding the material, it should be brought to
my attention immediately so that the difficulty can be overcome.
Virginia Standard: ES.6 a, b, c
The student will investigate and understand how to identify common rock types
based on mineral composition and textures and the rock cycle as it relates to the
origin and transformation of rock types.
Key Concepts:
a. igneous (intrusive and extrusive);
b. sedimentary (clastic and chemical);
c. metamorphic (foliated and unfoliated) rocks.
Essential Knowledge/Skills
This section has been taken directly from the SOL Framework and contains
information and skills that teachers are required to teach and students must
master to be successful on the state SOL tests.
Knowledge: ES.6
a. Igneous rock forms from molten rock that cools and hardens either below or on
Earth’s surface.
b. Sedimentary rocks may either form from rock fragments or organic matter bound
together or they are formed by chemical precipitation.
c. Metamorphic rocks form when any rock is changed by the effects of heat, pressure,
or chemical action.
d. Extrusive igneous rocks have small or no crystals resulting in fine- grained or glassy
textures.
e. Intrusive igneous rocks have larger crystals and a coarser texture.
f. Extrusive igneous rocks include pumice, obsidian, and basalt.
g. Intrusive igneous rocks include granite.
h. Sedimentary rocks are clastic or chemical
i. Clastic sedimentary rocks are made up of fragments of other rocks and include
sandstone, conglomerate, and shale.
j. Non-clastic sedimentary rocks include limestone and rock salt.
k. Metamorphic rocks can be foliated or unfoliated (nonfoliated).
l. Foliated metamorphic rocks have bands of different minerals. Slate, schist, and
gneiss are foliated metamorphic rocks.
m. Unfoliated metamorphic rocks have little or no banding and are relatively
homogenous throughout. Marble and quartzite are unfoliated metamorphic rocks.

Skills: ES.6
a. Interpret the rock cycle diagram.
b. Classify the following rock types as igneous, metamorphic, or sedimentary: pumice,
obsidian, basalt, granite, sandstone, conglomerate, shale, limestone, slate, schist,
gneiss, marble, and quartzite.
Essential Understandings
This section has been taken from the SOL Framework. It is important that
teachers and students have a complete understanding of all of the concepts
listed.



Rocks can be identified on the basis of mineral content and texture.
The processes by which they are formed define the three major groups of rocks.
The rock cycle is the process by which all rocks are formed and how basic Earth
materials are recycled through time.
Vocabulary
basalt – a dark colored extrusive igneous rock composed chiefly of calcium plagioclase
and pyroxene
chemical sedimentary rock – also called nonclastic; sedimentary rocks formed by
precipitation or left after evaporation
clastic – sedimentary rock formed from fragments of previously existing rocks
coarse-grained texture – large mineral grains
conglomerate – a clastic sedimentary rock composed of lithified beds of rounded gravel
mixed with sand
extrusive – igneous formed from lava that cools on the earth’s surface
fine-grained texture – small mineral grains
foliated – metamorphic rock whose minerals are arranged in parallel layers
gneiss – a coarse, foliated metamorphic rock formed from granite, in which bands of
granular minerals alternate with bands of flaky or elongate minerals
granite – light colored, coarse grained, intrusive igneous rock characterized by the
minerals orthoclase and quartz
igneous rock – rock formed from molten lava or magma
intrusive – igneous rock formed from magma that cools beneath the earth’s surface
lava – molten rock at the earth’s surface
limestone – nonclastic sedimentary rock form either by the precipitation of CaCO3 in
the deep ocean or from the accumulation of microscopic shells
magma – molten rock beneath the earth’s surface
marble – a metamorphic rock formed from limestone composed largely of calcite
(nonfoliated)
metamorphic rock – rock changed in form as a result of chemical reactions, heat,
and/or pressure
obsidian – extrusive igneous rock with a glassy texture
pumice – extrusive igneous glass with a great number of holes that remained in a rock
after trapped gas was unable to escape from solidifying melt; formed during a
pyroclastic eruption
quartzite – metamorphic form of sandstone (nonfoliated)
rock cycle – a diagram showing how the formation of igneous, sedimentary, and
metamorphic rocks are interrelated
rock salt – a chemical sedimentary rock that forms when large bodies of water
evaporate leaving behind thick layers of sodium chloride
sandstone – a clastic sedimentary rock in which the particles are dominantly of sand
size, from 0.062 mm to 2 mm in diameter
schist – a strongly foliated, coarsely crystalline metamorphic rock, produced during
regional metamorphism
sedimentary rock – rock formed by the compacting and/or cementing of sediments
shale – a clastic sedimentary rock (mudstone) that splits or fractures easily
slate – a compact, fine-grained metamorphic rock that is characterized by nearly sheetlike planes of breakage (foliated)
texture – the size and shape of the mineral crystals, or grains, in a rock
unfoliated – also called nonfoliated or recrystalized; a type of metamorphic rock
formed mainly by heat; parallel bands are not usually present.
Additional Related Vocabulary
The following terms are related to this unit and may be taught to help develop
a better understanding of the topic.
bituminous coal – commonly used coal, contains 85% carbon; also called soft coal
cementation – the process by which sediments are glued together to form rocks
compaction – a process by which sediments are squeezed into rock
concretion – round masses of calcium carbonate that often occur in layers of shale
crystal – solid in which the atoms or molecules are arranged in a definite pattern that is
repeated over and over again
diorite – an intrusive igneous rock with equal amounts of light and dark minerals
fossils – any evidence of ancient life preserved in rock, usually found in sedimentary
rock
gabbro – a dark, coarse-grained intrusive igneous rock, chemically equivalent to a
basalt
geode – hollow spheres of silica sometimes found in limestone, they may be lined with
calcite or quartz crystals
mud cracks – cracks that form when deposits of wet clay dry and contract
nodule – lump of mineral material such as chert sometimes found in limestone
ripple marks – formed by the action of winds, streams, waves, or currents on sand
scoria – an extrusive igneous rock with lots of holes and is denser than pumice
sediments – particles of rock or organic materials that have been carried along and
deposited by water, wind, or glaciers; small pieces of rock, shell, and other material
that are broken down over time by the process of weathering
stratification – the arrangement of sedimentary rock in visible layers
weathering – breaking down of rocks and other material at the earth’s surface.