This document defines and compares different types of rocks, including their formation processes and compositions. Intrusive rocks form deep underground and have large crystals, while extrusive rocks form on the surface and have small crystals. Felsic rocks are lighter in color with high aluminum, while mafic rocks are darker with more iron and magnesium. The document also discusses sedimentary rocks like conglomerate, sandstone, and shale formed from clastic deposits, as well as chemical/evaporite rocks and organic rocks like coal. Finally, it defines metamorphic rocks as those changed by heat and pressure, distinguishing between foliated rocks with layered minerals and non-foliated rocks with massive, unlayered structures.

2.  Intrusive: Rocks formed deep inside Earth
 Formed from magma
 Cool very slowly
 Have large crystals

3.  Extrusive: Rocks formed on or near Earth’s
surface
 Formed from lava
 Cool very rapidly
 Have small or no crystals

5.  Felsic:
 Light or red in color
 Usually Lower
density
 High content of
aluminum
 Mafic:
 Dark or green in color
 Usually Higher
Density
 High content of iron
or magnesium

6. COMPOSITION
Felsic Intermediate Mafic
Lighter---------------------------Color----------------------------Darker
Lower---------------------------Density--------------------------Higher
Intrusive
Course
Grained Granite Diorite Gabbro
Extrusive
Fine
Grained Rhyolite Andesite Basalt
Vesicular Pumice Scoria
Glassy Obsidian

7. INTRUSIVE

8. EXTRUSIVE

9. EXTRUSIVE

10. Intrusive

11. EXTRUSIVE

12. Felsic

13. Felsic

14. Mafic

15. Could be Both

17. • Definition:
– Small, solid pieces of material that
come from rocks or living things
like leaves, shells, etc.

18.  Clastic
 Formed from various rock fragments
 Deposited by water, wind, glaciers
 Classified by grain size and shape
 Formed from Cementation or Compaction

20.  Grain Size and Shape
Texture Grain Size Composition Comments Rock Name
Inorganic Land-Derived
Clastic
Pebbles, cobbles,
and/or boulders
embedded in sand, silt
and/or clay
Mostly quartz,
feldspar, and clay
minerals; may
contain fragments of
other rocks and
minerals
Rounded fragments Conglomerate
Angular fragments Breccia
Sand (0.2 to 0.006 cm) Fine to course grained Sandstone
Silt (0.006 to 0.0004
cm) Very fine grained Siltstone
Clay (less than 0.0004
cm)
Compact, cannot see
individual grains Shale

21.  Chemical
 Formed when minerals dissolved in water crystalize
 Think back to salt crystal lab
Crystalline
(Chemical)
Fine-grained;
crystals from
chemical
precipitates and
evaporates
Halite
Softer than a
fingernail, will not
react with acid, salt Rock Salt
Gypsum
Softer than a
fingernail, will not
react with acid Rock Gypsum
Calcite
Carbonate: will react
with acid Limestone

22.  Organic Sedimentary Rock
 Forms where the remains of plants & animals are
deposited
Bioclastic
(Organic)
Fine to course Calcite
Made of shells,
will react with
acid Coquina
Fine-grained Carbon
Dark in color;
made from plant
remains Coal

23. Coal
Coquina

25.  The term "metamorphic"
means "to change form.“
 These rocks have been put
under high pressure and
temperatures
 They are not melted in this
process, instead new
minerals and physical make
up change

26.  There are two types of
metamorphic rocks.
 Each is classified
according to its
composition and
texture.
 Foliated
 Nonfoliated.

27.  FOLIATED metamorphic
rocks are those in which the
minerals have been
flattened and pushed into
layers
 Examples of foliated rocks
are slate, and gneiss.

29.  NON-FOLIATED metamorphic rocks
do not display layers. Rather, they are
massive structures with no obvious
banding.
 The mineral grains grow and
rearrange, but they don’t form
layers.
 A good example of non-foliated rock is
quartzite or Marble

31.  Metamorphism can
occur in different
degrees
 The crystals can
rearrange themselves
without being melted
 A metamorphic rock
can go through
metamorphism