"What is streak?"
"A streak is the mark a mineral leaves when you rub it on an unglazed, porcelain tile. The tile - like some bathroom floor tiles - is known as a streak plate! The mark is actually a powder!"
"Dynamite! But why bother?"
"Sometimes the color of the streak is different from the color of the mineral - and that helps identify the mineral!"
"Cool! Sounds simple!"
"It is simple! But you have to be careful to test a fresh, unweathered (unaltered) part of the mineral! And some minerals, those that are harder than the streak plate, don't make a streak at all!"
"This sounds like something I could do!"

© 2001, David J. Leveson