Sandstone looks a lot like sand but is rough and hard.
Basalt is black with a some what flat texture.
Andesite is similar to basalt in the way that it's texture is flat but also rough and the color is light grey
Although it may look soft obsidian is a really tough rock and has a incredibly smooth texture and is incredibly easy to recognize because of the color black.
Granite is easily recognizable because of its black and white colors and rough texture.
Rhyolite is another igneous rock that looks just like any other rock because of it's some what smooth texture and it's gray color.
Slate has a flat like texture that's that's easily recognize able and a nice grey color.
Schist is light Grey with dark grey spots and a rough texture.
Gneiss Is light grey with orange spots and black lines with a rough texture.
Marble has a definite flat texture with an easily recognizable light grey.
Quartzite is light grey in some spots and dark grey in others it also has.
Coal is black with a flat and some times rough texture.
Travertine is a somewhat caramel brown with a once agin somewhat smooth somewhat rough texture.
Lime stone is light grey with a definite rough texture.
Shale is black and has a flat texture which makes it easy to identify