Question

quartz
amphibole
pyroxene
galena
if all four samples are placed together in a closed, dry container and shaken vigorously for 10 minutes, which mineral sample would experience the most abrasion?
a) quartz
b) amphibole
c) pyroxene
d) galena

1. the table below shows the hardness of some common items.

item	hardness
penny coin	3
iron nail	4.5
steel file	6

which mineral could be scratched by an iron nail, but not by a penny coin?
a) quartz
b) halite
c) dolomite
d) amphibole

1. the data table below shows a students observations of a mineral sample.

property	observation
color	brassy yellow
streak	green - black
density	5.0 g/cm³

based on the students observations, the mineral can best be identified as
a) magnetite
b) hematite
c) sulfur
d) pyrite

1. the diagram below shows the index minerals of mohs hardness scale compared with the hardness of some common objects.

index minerals	common objects
corundum	9
topaz	8
quartz	7	steel file
orthoclase	6	glass
apatite	5
fluorite	4
calcite	3	copper penny
gypsum	2	fingernail
talc	1

which statement is best supported by the diagram?
a) a fingernail will scratch calcite but not gypsum.
b) calcite will be scratched by a copper penny.
c) the mineral apatite will scratch topaz.
d) a steel file has a hardness of about 7.

Explanation:

Step1: Recall abrasion and hardness relationship

Minerals with lower hardness experience more abrasion when in contact with harder - minerals.

Step2: Determine the hardness of given minerals

From the Mohs hardness scale, quartz has a hardness of 7, amphibole has a hardness of 5 - 6, pyroxene has a hardness of 5 - 6, and galena has a hardness of 2.5.

Step3: Identify the mineral with lowest hardness

Galena has the lowest hardness among the four minerals. So, it will experience the most abrasion.

Step1: Analyze hardness range for the second question

A mineral that can be scratched by an iron nail (hardness 4.5) but not by a penny coin (hardness 3) should have a hardness between 3 and 4.5.

Step2: Check hardness of each option

Quartz has a hardness of 7, halite has a hardness of 2 - 2.5, dolomite has a hardness of 3.5 - 4, amphibole has a hardness of 5 - 6. Dolomite fits the hardness range.

Step1: Match properties to known minerals for the third question

A mineral with metallic luster, brassy - yellow color, green - black streak and density of 5.0 g/cm³ is pyrite.

Step1: Analyze each statement for the fourth question

A fingernail (hardness 2.5) will scratch gypsum (hardness 2) but not calcite (hardness 3), so option A is incorrect. Calcite (hardness 3) will be scratched by a copper penny (hardness 3), so option B is correct. Apatite (hardness 5) will not scratch topaz (hardness 8), so option C is incorrect. A steel file has a hardness of 6, not about 4, so option D is incorrect.

Answer:

D. galena