Question
click below
click below
Question
Normal Size Small Size show me how
Diamonds 4-6
Question | Answer |
---|---|
How far beneath the earth’s surface do diamonds form? A. 15 to 30 miles (25 to 50 km) B. 30 to 50 miles (50 to 75 km) C. 50 to 90 miles (75 to 140 km) D. 90 to 120 miles (140 to 190 km) | D. 90 to 120 miles (140 to 190 km) |
The deep vertical formations through which diamonds traveled to the surface are called A. drifts. B. pipes. C. cratons. D. alluvials. | B. pipes. |
The first authenticated diamond discovered in South Africa is named the A. Eureka. B. Cullinan. C. De Beers. D. Star of Africa. | A. Eureka. |
Most of the world’s kimberlite pipes A. are located close to large cities. B. are being mined for diamonds at the present. C. do not contain diamonds in profitable quantities. D. are believed to contain great quantities of diamonds. | C. do not contain diamonds in profitable quantities. |
The correct conditions for diamond formation exist under A. cratons. B. volcanic ash. C. oceanic crust. D. large mountain ranges. | A. cratons. |
Scientists have found that diamonds form in two types of rocks, called A. marble and shale. B. sandstone and schist. C. peridotite and eclogite. D. kimberlite and lamproite. | C. peridotite and eclogite. |
Diamond and graphite are both made of A. carbon. B. helium. C. oxygen. D. nitrogen. | A. carbon. |
Diamond is hard and graphite is soft because of the difference in A. their atoms. B. their transparency. C. their chemical formulas. D. the way their atoms fit together. | D. the way their atoms fit together. |
The proper environment for diamond formation includes the right temperature, pressure, and A. molten lava. B. indicator minerals. C. the availability of carbon. D. the presence of trace elements. | C. the availability of carbon. |
Subduction occurs when A. volcanoes erupt. B. mountains collide. C. tidal waves sweep over landmasses. D. two of the earth’s crustal plates collide. | D. two of the earth’s crustal plates collide |
Diamonds were delivered to the earth’s surface as recently as A. 20 billion years ago. B. 20 million years ago. C. 1 million years ago. D. 10,000 years ago. | B. 20 million years ago. |
The three main components of the earth are the crust, mantle, and A. core. B. center. C. stratosphere. D. subduction zone. | A. core. |
Before arriving at the earth’s surface, diamonds might remain in the mantle for as long as a few A. days. B. hours. C. hundred years. D. hundred million years. | B. hours. |
During emplacement, if diamonds are exposed to high temperature along with decreased pressure for a long period, they will A. melt. B. explode. C. vaporize. D. convert to graphite. | D. convert to graphite. |
Diamond deposits found at the ocean’s shore are A. marine deposits. B. primary deposits. C. industrial deposits. D. shoreline deposits. | A. marine deposits. |
For more than 2,000 years, the only known diamond sources were A. alluvial. B. primary. C. kimberlite pipes. D. ancient volcanic craters. | A. alluvial. |
Diamonds are more concentrated in A. marine deposits. B. primary deposits. C. volcanic deposits. D. mountain deposits. | A. marine deposits. |
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. | A. are not profitable. |
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. | A. its ore grade. |
Most of the diamonds mined today come from A. pipes. B. beaches. C. riverbeds. D. the ocean floor. | A. pipes. |
Diamonds classified as cuttable can be 100 times more valuable than A. marine diamonds. B. alluvial diamonds. C. industrial diamonds. D. gem-quality diamonds. | C. industrial diamonds. |
Indicator minerals in kimberlite and lamproite might include tiny A. emeralds. B. sapphires. C. amethysts. D. diamonds. | D. diamonds. |
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. | C. look for the oldest parts of the earth’s crust. |
Gravity sorting separates diamonds from A. river gravels. B. lighter materials. C. heavier materials. D. indicator minerals. | B. lighter materials. |
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. | B. industrial quality. |
To focus their search for diamond deposits, geologists look for A. river gravels. B. trace elements. C. indicator minerals. D. small grains of graphite. | C. indicator minerals. |
Diamond rough suitable for use in jewelry is called A. cuttable. B. Grade A. C. top-quality. D. jewelry-quality | A. cuttable. |
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. | D. produces diamonds whose value is higher than the mine’s operating costs. |
The concentration of diamonds within a pipe is called A. drift. B. ore grade. C. overburden. D. rough grade. | B. ore grade. |
Shortly before the discovery of the South African deposits, the world’s major diamond producer was A. India. B. Brazil. C. Russia. D. Canada. | B. Brazil. |
Most diamonds from Australia are A. large, but of poor color. B. large and near-colorless. C. small and poor in quality. D. small, but of good quality. | C. small and poor in quality. |
Russia’s significant diamond deposits are in A. Siberia. B. Belorussia. C. the Crimea. D. the Kaliningrad Oglast. | A. Siberia. |
African diamonds are recovered from A. pipe deposits only. B. alluvial deposits only. C. pipe and alluvial deposits. D. pipe, alluvial, and marine deposits. | D. pipe, alluvial, and marine deposits. |
The largest percentage of world diamond production (by weight) is mined in A. Brazil. B. Angola. C. Australia. D. Indonesia. | C. Australia. |
Chambering and block caving are methods used in A. mining diamond pipes. B. mining alluvial deposits. C. testing the productivity of diamond pipes. D. testing the productivity of alluvial deposits. | A. mining diamond pipes. |
Diamond’s attraction to grease is used in A. separating diamond from ore gravels. B. fashioning diamond into fancy shapes. C. separating gem-quality from industrial diamonds. D. sorting and grading operations at the Diamond Trading Company. | A. separating diamond from ore gravels. |
Most modern diamond-mining operations are A. done with simple hand tools. B. small in scale and not very expensive. C. large in scale and extremely expensive. D. performed in temperature-controlled environments. | C. large in scale and extremely expensive. |
A horizontal tunnel drilled through a diamond pipe is called a A. path. B. drift. C. shaft. D. channel | B. drift. |
Dirt and clay are washed from diamond-bearing ore by A. cleaners. B. agitators. C. scrubbers. D. grease belts. | C. scrubbers. |
A. drift mining. B. open-pit mining. C. open-air mining. D. original-source mining. | B. open-pit mining. |
Dense media separation is based on the fact that A. diamonds stick to grease. B. most diamonds fluoresce when X-rayed. C. diamonds float to the top of a mix of gravels. D. diamonds sink to the bottom of a mix of gravels. | D. diamonds sink to the bottom of a mix of gravels. |
The Argyle mine is famous for diamonds that are A. pink. B. blue. C. large. D. colorless. | A. pink. |
The shift in emphasis from alluvial to primary diamond mining was due to A. improved technology. B. environmental concerns. C. depletion of secondary sources. D. political and governmental pressures. | A. improved technology. |
Russia’s diamond sources are almost all A. alluvial. B. primary. C. depleted. D. secondary. | B. primary. |