Color, Luster, and Streak

Which of the below are lusters that a mineral can have?

• Metallic

• Non-Metallic

• Earthy

• Watery

• Wood-like

What do you rub a rock across to observe a streak?

• Glass

• Penny

• Nail

• Unglazed Tile

What color is pyrite's streak?

• Green-brown

• Red

• Golden

• Blue

Do minerals have a consistent color (i.e., are all quartz the same color)?

• Yes, minerals have a set chemical structure so color is the same

• Yes, minerals have a set crystal structure, so color is the same

• No, minerals have variable colors as seen in minerals like calcite and quartz

• No, a mineral can be different colors because it can have different chemical structures

What is the luster of this mineral sample?

• Glassy

• Greasy

• Metallic

• Pearlescent

This biotite mica has what kind of luster?

• Glassy

• Vitreous

• Waxy

• Metallic

Which of the following statements is false?

• A mineral can have either a metallic or non-metallic luster.

• The streak of a mineral always matches the color of the mineral.

• To test streak, you rub a mineral across a streak plate.

• Identifying minerals by color alone is a bad idea- minerals can come in many different colors.

This is an obvious property of a mineral that can be a problem when used by itself to ID minerals

(a)  

This is what we call the powder left behind on an unglazed tile that has had a mineral rubbed across its surface

(a)  

Minerals have a (a)   , which can be classified as metallic or non-metallic.