Streak Test
Streak test is scratching a mineral across a rough plate to see the color it leaves behind.
Think of it this way
A crayon looks one color on the outside but leaves a different color when you rub it on paper. The waxy shell hides the true color inside. Scientists do the same with minerals — they rub each one across a rough tile. The streak color left behind tells minerals apart better than surface color does.
Explaining streak test by grade level
Some rocks look one color but leave a different color mark. Try rubbing a rock on a white tile. The line it makes is called a streak. That streak color helps you name the rock.