Review for Rocks Test
When you use a scratch test to try to scratch a metal or glass plate with your rock, or try
to scratch your rock with a penny, a fingernail, or steel nail what property are you
checking for?
A: hardness
What is cleavage?
A: The property of a mineral to split easily along flat surfaces.
What is luster?
A: The way a mineral reflects light from its surface.
What is a gemstone?
A: An uncut (raw) hard, colorful mineral that has a brilliant or glassy luster and is
valued for it’s appearance.
What is a clastic sedimentary rock?
A: A rock that is formed when small pieces of other rocks are squeezed together under
high pressure.
Give at least one example of a clastic sedimentary rock.
A: (Many answers but some are): conglomerate, breccia, sandstone, shale, siltstone or
claystone.
How does granite form?
A: Granite is an igneous rock that forms when magma cools and hardens under the
surface of the earth, resulting in a coarse grained rock (large crystals). It is made up
mostly of the minerals potassium and plagioclase feldspars, quartz, biotite, amphibole
and horneblende.
When the large crystals of granite are put under extreme heat and pressure the crystals
change to look like the grain in wood (bands or lines), this is an example of forming a
foliated metamorphic rock called gneiss.
Metamorphic rocks are divided into two main groups, label the groups and draw a picture
of one rock that would be in each group.
1. Foliated
(Draw a rock with lines in it)
2. Non-Foliated
(Draw a rock with no lines in it)
Name at least two minerals that you saw in at least one rock of each type (igneous,
sedimentary and metamorphic).
A: (Many answers but some are): potassium feldspar, plagioclase feldspar, quartz,
biotite, olivine, amphibole and horneblend.
Why are metamorphic rocks often used to make buildings?
A: Since the rock has been exposed to high heat and pressure it often has a very fine
even grain which makes it easy to carve, sculpt and polish.
Why is slate used to make roofs, floors and walkways?
A: Since the rock splits very easily into flat pieces it works well as flooring and roofing
material.
What mineral is a coral reef made up of?
A: Calcite (made of calcium, carbon and oxygen).
What kind of rock do coral reefs form?
A: Limestone
Where do coral reefs form?
A: They form in the shallow (less than 120 feet), warm, clear water of tropical oceans.
Sedimentary rocks are divided into three main groups, label the three groups and draw a
picture of one rock that would be in each group.
1. Clastic
(Draw a rock made of
other rock pieces)
2. Organic
(Draw a rock that is
made from once-living
things)
3. Chemical
(Draw a rock that formed
from minerals dissolved
in solution.
How do sediments form?
A: They form from the erosion (breaking down) of other rocks which may be from
running water, wind or ice.
What kind of rock is made from deposition?
A: Sedimentary rock (also involves compaction and cementation)
What kind of rock forms after being melted?
A: Igneous rock
How did the ocean get salty?
A: The ocean became salty as the weathering (erosion) of rocks released minerals,
including salt, into the oceans over millions and millions of years.
Can you label the rock cycle?
A: Refer to page 115 in the textbook if the attached copy is too hard to read.