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Rocks
How can rocks be identified?
Rocks may show ripple marks,
mudcracks, raindrops and
fossils. Can often see sand,
pebbles, or stones in the rock.
Type of Rock
Sedimentary
How Rock Is Formed
Rock particles settle from
different areas (usually in
water) and are cemented
together.
Examples
Conglomerates,
limestone, rock salt, rock
gypsum, chert,
Igneous
Cooling magma (above or
below the ground).
Often appears shiny and
glasslike with no crystals. May
have tiny holes and spaces
where gas bubbles have
escaped.
Granite, diorite, gabbro,
rhyolite, andesite, basalt,
pumice, scoria, obsidian,
basalt
Metamorphic
Any rock that has changed
because of temperature and
pressure.
Often have ribbonlike layers
and may have shiny crystals.
Slate, phyllite, schist,
gneiss, quartzite, marble