Download GLOSSARY ROCKS AND MINERALS

GLOSSARY
ROCKS AND MINERALS
boulder—a large stone moved by nature
from its original bed
calcite—mineral which is in limestone,
marble, and chalk
crust—the rocky, uppermost layer of
the Earth
eruption—the bursting forth of lava
from a volcano
extrusive rock—rock formed from lava
after it has reached the surface of the
Earth.
facet—any of the many polished sides of
a cut gemstone
feldspar—a mineral found in igneous
rocks
gem—a precious, rare and perfect stone,
especially when set as an ornament
granite—an abundant, strong, durable
igneous rock useful in the construction
of buildings and monuments.
hardness—the measurement of how
easily a mineral is scratched
igneous rock—rock formed from magma
as it cools and hardens.
intrusive rock—rock formed when
magma works its way between rocks and
hardens beneath the surface of the
Earth
jewel—a precious stone or gem,
especially one set in precious metal
lava—melted rock that pours out onto
the surface of the Earth from a volcano
limestone—a type of sedimentary rock
made from seashells and tiny sea animals
which makes an excellent building
material because it can be carved easily.
magma—melted rock beneath the
Earth‛s surface
metamorphic rock--rock created
when igneous or sedimentary rock is
changed by heat and pressure.
minerals—natural substances that make
up rocks and have a chemical composition
and a crystalline structure.
pebble—a small, rounded fragment of
rock
pumice—an igneous rock formed from
cooled lava that is light and contains air
bubbles.
quartz—a common, very hard mineral
found in all three major types of rocks.
rock—a natural solid material that makes
up the Earth‛s crust, usually consisting
of a mixture of minerals.
Sand—a hard, granular rock material
that is smaller than gravel and larger
than silt.
Sedimentary rock—rock formed from
many layers of sand, mud, rock
fragments and plant and animal remains
that have undergone pressure from
above.
stalactite—a limestone formation found
in some caves that hangs down from the
ceiling and is formed when ground water,
rich in carbon dioxide, dissolves the
mineral calcite from limestone directly
above
stalagmite—a limestone formation found
in some caves that rises up from the
floor and is formed when water, dripping
on the floor, carries with it deposits of
calcite.
stone—a small piece of rock
strata—layers of rock
volcano—an opening in the Earth‛s crust
through which lava, dust, and hot gases
are spewed out.