Download Rocks and Minerals

Rocks and Minerals
Hardness- a mineral’s ability to resist being scratched
Igneous rocks- rock that forms when melted rock hardens
Luster- this describes how a mineral’s surface looks when light
reflects from it
Metamorphic rocks- a rock that has been changed by high heat
and great pressure
Mineral- a natural solid that has its particles arranged in a
crystal pattern
Rock- a material made up of one or more minerals
Rock cycle- this is the pattern of slow changes in rocks from
one kind to another
Sedimentary rocks- these rocks form when rock pieces
deposited over time are squeezed and stuck together
Streak- when you rub a mineral against a white tile, this is the
color of the powder left behind
 Be sure to understand (not memorize) the Moh’s scale of
hardness. 1 is the softest and 10 is the hardest. Anything
that is harder than something else can scratch it. For
example, apatite with a hardness of 5 could be scratched
by glass with a hardness of 6, but not by a penny with a
hardness of 3.
 Halite is another term for table salt.
 A rock with pieces of seashells in it is sedimentary.
 Scientists use hardness, streak, and luster to classify
minerals.
 Crushed graham crackers that are mixed with melted
butter and pressed into a pie pan to make a crust could be
a model of how an igneous rock changes into a
sedimentary rock because sedimentary rocks are formed
when other rocks are broken up and then pressed, as
happens when graham crackers are broken up to make a
graham cracker crust.
 A piece of pumice is lighter than a piece of obsidian of
equal size because pumice has tiny holes in it that are
caused by gases escaping from lava as it cools. This
makes it lighter than a same-sized piece of obsidian.
 You are not likely to find a fossil in metamorphic rock or
igneous rock because the pressure and heat required to
form metamorphic or igneous rock would destroy any
fossils that might be contained in the rock.
 A rock is different from a mineral because a mineral is a
solid material with a repeating crystal pattern. Rocks can
be made up of one or more minerals.