Diamonds 5 — Exploring for Diamonds

Question 1

The concentration of diamonds within a pipe is called

A.	drift.
B.	ore grade.
C.	overburden.
D.	rough grade.

Answer 1

B. ore grade.

Question 2

To focus their search for diamond deposits, geologists look for

A.	river gravels.
B.	trace elements.
C.	indicator minerals.
D.	small grains of graphite.

Answer 2

C. indicator minerals.

Question 3

Diamond rough suitable for use in jewelry is called

A.	cuttable.
B.	Grade A.
C.	top-quality.
D.	jewelry-quality.

Answer 3

A. cuttable.

Question 4

A mine’s potential profitability depends in part on

A.	its ore grade.
B.	its location on a craton.
C.	having a small, compact pipe.
D.	a good kimberlite-to-lamproite ratio.

Answer 4

A. its ore grade.

Question 5

Indicator minerals in kimberlite and lamproite include tiny

A.	emeralds.
B.	sapphires.
C.	amethysts.
D.	diamonds.

Answer 5

D. diamonds.

Question 6

The first step in exploring for diamonds is to

A.	collect bulk samples of ore.
B.	search for ancient volcanoes.
C.	look for the oldest parts of the earth’s crust.
D.	examine river gravels for indicator minerals.

Answer 6

C. look for the oldest parts of the earth’s crust.

Question 7

Most of the diamonds mined today come from

A.	pipes.
B.	beaches.
C.	riverbeds.
D.	the ocean floor.

Answer 7

A. pipes.

Question 8

For more than 2,000 years, the only known diamond sources were

A.	alluvial.
B.	primary.
C.	kimberlite pipes.
D.	ancient volcanic craters.

Answer 8

A. alluvial.

Question 9

Diamonds classified as cuttable can be 100 times more valuable than

A.	marine diamonds.
B.	alluvial diamonds.
C.	industrial diamonds.
D.	gem-quality diamonds.

Answer 9

C. industrial diamonds.

Question 10

Diamonds are more concentrated in

A.	marine deposits.
B.	primary deposits.
C.	volcanic deposits.
D.	mountain deposits.

Answer 10

A. marine deposits.

Question 11

A profitable mine

A.	is close to a source of water.
B.	has a high percentage of microdiamonds.
C.	meets governmental and environmental regulations.
D.	produces diamonds whose value is higher than the mine’s operating costs.

Answer 11

D. produces diamonds whose value is higher than the mine’s operating costs.

Question 12

Diamond deposits found at the ocean’s shore are

A.	marine deposits.
B.	primary deposits.
C.	industrial deposits.
D.	shoreline deposits.

Answer 12

A. marine deposits.

Question 13

Gravity sorting separates diamonds from

A.	river gravels.
B.	lighter materials.
C.	heavier materials.
D.	indicator minerals.

Answer 13

B. lighter materials.

Question 14

Diamond rough suitable for use in tools, drills, and abrasives is

A.	cuttable quality.
B.	industrial quality.
C.	primarily from marine deposits.
D.	a byproduct of the exploration process.

Answer 14

B. industrial quality.

Question 15

Only a small percentage of known diamond deposits are mined because most

A.	are not profitable.
B.	are too close to populated areas.
C.	are too far from populated areas.
D.	require expensive government permits.

Answer 15

A. are not profitable.