METAMORPHIC ROCKS LAB
PROBLEM: How can you
identify metamorphic rocks?
Science - Metamorphic Rocks, Swift
GH microscope or Hand
Part I: General Questions
Answer each of the following questions.
1. Can metamorphic rocks form on the Earth’s
surface? Explain your answer.
2. In what areas of the Earth is contact
metamorphism likely to occur?
3. Where might regional metamorphism take place?
Part II Examining Metamorphic Rocks and Minerals Look
at each of the metamorphic rock specimens. Carefully answer the
questions for each.
1. MUSCOVITE AND BIOTITE MICA
Muscovite and biotite are both flat silicate
minerals. This is because the silica compounds they contain are joined
together to make sheets, like the pages of a book. Mica commonly forms
under metamorphic conditions. However, you find mica in igneous and
A. What properties does mica have that could
associate it with metamorphic rocks?
B. What is the difference between the two micas?
C. How can you recognize mica in rocks?
Garnets are most common in metamorphic rocks
formed under moderate temperature and pressure. It comes in various
colors ranging from red to green. It forms a characteristic 12 sided
A. Describe your crystal.
B. Can a steel nail scratch your specimen?
3. MICA SCHIST
Mica schist is a common metamorphic rock that is
produced by regional metamorphism. The shiny look of schist is one of
its key characteristics. The schist also has a nicely developed
foliation. The word foliation comes from the Latin "folia"
A. In what way does schist have a
B. Are the minerals present in this schist visible
with the naked eye?
C. What is the sparkly mineral visible in this
4. MARBLE is
metamorphosed limestone. Limestone is a sedimentary rock that is mainly
composed of calcite, derived from the shells of living organisms like
clams and snails. Marble can be produced by contact or regional
metamorphism. Marble does not develop foliation like schist, because the
calcite crystals are all about the same size. There is no way for them
to line up. Marbles often contain other minerals, such as quartz, mica,
A. Is this sample of marble fine (small) or coarse
B. What happens when dilute HCl is dropped on
C. How many types of minerals are in this specimen
Quartzite is a very hard metamorphic rock. It can
be made by contact or regional metamorphism. Like marble, it is made of
crystals that are all about the same size, so it does not have
foliation. Primitive people often used quartzite to make bladed weapons
like knives and arrowheads.
A. From its name, what mineral makes up quartzite?
B. Can you tell this just by looking at the rock?
Explain your answer.
C. Which would be more useful in identifying
quartzite, a bottle of HCL or a steel knife? Explain your answer
D. What was the likely mineral composition of the
rock from which quartzite was made?
E. You saw a rock in the sedimentary lab that
could be this original rock. Can you guess which one it is?
Slate is formed by regional metamorphism. It is a
low-grade metamorphic rock, meaning that it was created by relatively
low temperature and pressure. Schist, which you have already examined,
is a medium-grade metamorphic rock.
A. Describe your piece of slate.
B. Slate is formed under low to moderate pressure
and temperature conditions. Does slate ring when lightly dropped?
C. Can you think of any uses for a large piece of
slate? (Hint: think about buildings.)
D. Which sedimentary rock was slate most likely
Gneiss is a high-grade metamorphic rock. It is
common only in areas of regional metamorphism. Several different rocks,
such as granite, schist, and diorite can be metamorphosed to make
gneiss. This is one of the most difficult things to understand about
metamorphic rocks. Different preexisting rocks can produce the same kind
of metamorphic rock.
A. Describe your piece of gneiss. Make sure you
look at the arrangement of the minerals.
B. Is gneiss banded or layered?
C. What makes up the different bands?
Serpentinite is a metamorphic rock produced
largely by metamorphism along fault zones. The original rock is often an
igneous rock like gabbro or basalt. Serpentinite is composed mainly of
the mineral serpentine. Serpentinite is the state rock of California.
However, the state legislators didn't know the difference between
serpentinite (the rock) and serpentine (the mineral), and voted to make
"serpentine" the state rock.
A. Where do you think serpentinite got its name?
B. How does serpentinite "feel?"
C. Can you think of any uses for serpentinite?
Hornfel is a fine grained metamorphic rock that is
nonfoliated. It usually forms under low pressure and varying ranges of
temperature. It is difficult to distinguish.
A. What igneous rock could you confuse hornfels
B. Describe your sample.
Phyllite is a metamorphic rock that has not been
under as much pressure as slate. It is usually derived from mudstone or
1. Describe your specimen?
2. What is the difference of dropping phyllite
about 6 cm from a hard surface and a piece of slate?