Name________________________________________________________________Period__________
Sedimentary Rock Lab
Use the diagram and information on the right to answer the questions below.
1. Fill in the sedimentary rock types and sedimentary rocks described in the following table.
Description
Sedimentary rock
Rock name
type (organic,
chemical, or clastic)
The sediment particles are formed by
chemical precipitation, are too small
to see with an unaided eye, and are
made of calcite.
The sediment particles are mixtures
of sizes that range between 3.0 and
20.0 mm.
The sediment particles are pieces of
shells.
The sediment particles are sandsized.
The sediment particles are parts of
plants and animals.
2. What is chemical precipitation?
3.
Where do sediments come from that form clastic sedimentary rocks?
4.
Briefly describe each of the rocks below from the rock samples:
a. Organic limestone
5.
b.
Coal
c.
Chemical limestone
d.
Rock salt
e.
Gypsum
f.
Conglomerate
g.
Sandstone
h.
Shale
If you found a piece of limestone at the top of a mountain, what would you conclude about how the Earth
has changed?
Classifying Sedimentary Rocks
Sedimentary rocks may be classified into three groups based on what they are made of and how they
were formed. If the sediments that make up the rocks came mostly from the shells of animals or from the body
parts of plants and animals, the rocks would be classified as organic sedimentary rocks. If the sediments were
produced from elements that were dissolved in water but later came out of solution, the rocks would be classified
as chemical sedimentary rocks. When elements come out of solution, the elements are said to have precipitated
and the process is called chemical precipitation. Chemical sedimentary rocks are also called evaporates. If the
sediments were formed from particles that were weathered from other rocks, the rocks are called clastic
sedimentary rocks. Clastic sedimentary rocks are classified on the basis of the size of the sediment particles that
the rock is made of.
Sedimentary rocks can tell you a lot of information about how the Earth’s surface has changed over time.
Here are some examples:
 Limestone forms in shallow oceans.
 Coal is formed from the remains of dead plant materials.
 Conglomerate forms from streambeds and alluvial fans.
 Sandstone forms from sand dunes and beaches.
Common Sedimentary Rocks
Sedimentary Rock Type
Organic Sedimentary Rocks
Formed from the remains of
living things such as plants and
animals
Chemical Sedimentary Rocks
Formed when elements that
were dissolved in water come
out of solution
Clastic Sedimentary Rocks
Formed when the particles that
are weathered from other rocks
are cemented together to form
a new rock
Particle size or composition
If the rock is made mostly of
shells
If the rock is made mostly of
plant and animal remains
Sediment particles too small
to be seen with unaided eye.
If the mineral that comes out
of solution is

Calcite

Dolomite

Halite

Gypsum
If the particles are

Boulder-sized, cobblesized, or pebble-sized
(larger than 2mm)

Sand-sized (0.06 to 2
mm in size)

Clay-sized (smaller than
0.06 mm)
Rock name
Limestone
Coal (bituminous)
Then the rock is

Limestone

Dolomite

Rock Salt

Gypsum
Then the rock is

Conglomerate

Sandstone

Shale