Evidence of ancient life, usually.
me
gothic
the look and feel of sedimentary rocks are sometimes hard and smooth or hard and rough
rainbow rocks look raibowbut it has the colors [yellow silver gold red ]
Sedimentary rocks
Igneous rocks look different depending on how fast the magma cools.
it look like a magam
fossils
may-be is because all rocks don't look the same is different names and shape
You could look for similar fossils in the rocks. If they rocks contain the same type of fossil, they must be around the same age.
red rocks
You get a magnifying glass and look at them