6.6 C Minerals

The appearance of the surface of a mineral when it reflects light is known as ―

• streak

• luster

• conductivity

• hardness

The ability of one mineral to scratch another mineral is determined by the mineral’s —

• luster

• streak

• color

• hardness

A student is testing several minerals in science class. First, the student scratched the

minerals across a tile and then scratched the minerals with a copper penny and a steel tool.

What physical properties is the student testing?

• Color and state

• Streak and hardness

• Luster and conductivity

• pH and fracture

AA student found a pretty rock while hiking with her family. She discovered that the rock will

scratch glass, but not her steel knife.

According to the Mohs Hardness Scale shown above, what does the student know about the

rock?

• It is harder than quartz, but softer than topaz.

• It is harder than corundum, but softer than gypsum.

• It is harder than calcite, but softer than fluorite.

• It is harder than fluorite, but softer than quartz.

A streak test used to identify minerals requires —

• studying crystals with a magnifying glass

• scratching the mineral with an iron nail

• identifying the color of the powdered mineral

• observing how it reflects light from its surface

Which two physical properties of minerals can be observed without touching the minerals?

• Color and streak

• Luster and color

• Streak and hardness

• Hardness and luster

Which two physical properties of minerals can be observed by scratching the mineral against

other substances?

• Color and streak

• Luster and streak

• Streak and hardness

• Hardness and luster

Hematite is a mineral that comes in a variety of colors including black, grey, silver, brown and

red. A streak test is used to help determine the identity of hematite.

Why would a streak test be conducted on hematite to determine its identity?

• The streak changes depending on the color of hematite.

• The streak is the same color no matter the color of the hematite.

• The streak determines the hardness of the hematite.

• The streak changes depending on the luster of the hematite.

One of the most important tests for identifying minerals is the Mohs Hardness Test. This test

compares the resistance of a mineral to being scratched by ten reference minerals known as

the Mohs Hardness Scale. The test is useful because most samples of a given mineral are

very close to the same hardness. This makes hardness a dependable property for identifying

most minerals.

Which statement correctly represents a mineral with a hardness of 7?

• The mineral cannot be scratched by apatite, but can be scratched by feldspar.

• The mineral can scratch calcite, but cannot scratch apatite.

• The mineral can scratch apatite and every mineral with a hardness scale number higher

  than 7.

• The mineral can scratch apatite and every mineral with a hardness scale number lower

  than 7.