What is a substance that is found naturally in the earth and has a crystalline structure?

What is a mineral that exists naturally in the earth's crust as a single, uncombined element?

What is a geometric structure composed of atoms or molecules in an orderly arrangement?

What is a flat surface of a crystal?

What is a line of powder left on a piece of unglazed porcelain by a mineral?

What is the way light is reflected from the surface of a mineral?

What is the resistance of a smooth surface of a mineral to being scratched?

What is a tendency of a mineral to break readily along certain flat surfaces, producing fragments with the same shape as the parent mineral?

What is glowing when exposed to ultraviolet light in a darkened room?

What is glowing for a while after being exposed to ultraviolet light and then placed in the dark?