E.6.2

Jacob cannot scratch a mineral sample with his fingernail, but he observes that he can scratch the mineral sample with a piece of metal. What physical property of the mineral sample is Dennis investigating?

• cleavage

• hardness

• luster

• streak

Minerals are identified and sorted by different characteristics. Luster is one way to sort minerals into different types. What is a mineral’s luster?

• The color it makes when rubbed on a tile

• The mineral’s elements and their arrangement

• The way light reflects from its surface

• The way it breaks when you strike it with a hammer

One of the properties of a mineral that is useful for identification is its streak color. What is the streak color of a mineral?

• The ability to scratch a reference mineral

• The color of a fine powder of the mineral

• The way it forms faces when it is broken

• The way that the mineral’s surface reflects light

How are rocks and minerals different?

• Minerals have definite chemical properties, and rocks are made of many minerals.

• Rocks have definite shapes, and minerals have different shapes and colors.

• Minerals form naturally on Earth’s surface, and rocks do not.

• Rocks are always soft, and minerals are always very hard.

Brenda noted that mica breaks along smooth lines. What property of mica was Brenda observing?

• hardness

• luster

• cleavage

• streak