Encyclopedia of Global Resources part 34 pot

Natural Resources Deserts of the world hold most of the reserves of oil, natural gas, and coal, and they therefore serve as a source of natural wealth for many countries in the Middle Ea

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In the United States, cool deserts (sagebrush grass

and salt-desert shrub types) occur in old lake beds

Ancient Lake Bonneville in northern Utah and Lake

Lahontan in Nevada once occupied much larger

ar-eas and dominated the landscape These deserts are

also influenced by the Sierra Nevada and Cascade

Mountain ranges, which cast a rain shadow effect on

their eastern valleys Intermittent drainages (wadis or

arroyos) often cut across desert landscapes; they

con-tain running water only during or immediately after a

rainfall event These drainages support unique

vege-tation and serve as important habitats for birds and

other animals

Another major feature of deserts is that nutrients

are often limiting Soil nitrogen and organic matter

are especially low in these ecosystems Free-living and

symbiotic nitrogen-fixing bacteria are scarce in deserts

Research indicates that lichens and algae, forming

crusts on desert soils, may be the major source of soil

nitrogen for plant growth

Desert Adaptations

Rainfall events occur infrequently in deserts Both

plants and animals must have adaptations to take

ad-vantage of these episodic periods of available water to

survive in these harsh environments Thus one sees

flushes of desert flowers during spring and summer

months, especially in years when rainfall is abundant

These same flowers may not be seen again for several

years Desert plants exhibit several adaptations that

al-low them to exist successfully under these stressful

conditions Some plants, such as mesquite, have deep

root systems that allow access to deep sources of water

They do not have to rely on rainfall during the

grow-ing season Some plants have dense, shallow root

sys-tems that allow them to tap soil water in the soil

sur-face from light showers Some plants have both types

of root systems Cactus and other succulents have the

ability to store water in their tissues for use during

pe-riods of low rainfall Some plants, such as the creosote

bush, shed many leaves to reduce transpirational

re-quirements Others have few stomata on their leaf

sur-faces, thereby reducing transpirational stress These

stomata tend to close and restrict transpiration

Des-ert soils are often high in salt content from surface

evaporation of rainfall that does not penetrate far into

the soil, and plants growing on saline soils have special

adaptations for coping with these conditions

Animals also have many adaptations to desert

condi-tions Some desert animals can live in dormant stages

during unfavorable periods Many exhibit no definite breeding season and can breed whenever conditions are favorable Some, including birds, can conserve water by reducing loss through concentrated urine Some desert animals obtain most of their water through the food they eat Many are nocturnal, thereby avoid-ing the high temperatures of the day Intermediate-sized and small mammals often burrow to escape the heat and find more favorable conditions

Conservation and Prevention Issues Desert plants and animals are frequently under threat from a variety of natural and human-related activities Since water resources are so scarce, any external fac-tor that changes the water cycle or the availability of water at critical times may threaten organisms In some cases the existence of desert plants and animals

is not obvious, and adequate information on their sta-tus is lacking

Many desert landscapes were formed by erosion, but changes may be very slow and difficult to ascer-tain For example, there has been much concern over the increase in desert areas in the world The word

“desertification” has been used to describe the degra-dation of arid and semiarid areas into desertlike envi-ronments For some time nearly all observers believed that the Sahara Desert was expanding, but this has be-come a subject of debate Detailed remote sensing analyses have suggested that the Sahara Desert may expand and contract, perhaps in response to climatic cycles In many areas in Africa, such as the Sahel, live-stock populations are increasing to support the ex-panding human population During the dry season, woody plants supply needed high-quality forage for these animals These same woody plant resources are also heavily exploited for fuel wood despite re-strictions placed on their harvest Depletion of these valuable woody plant resources could have serious consequences for these delicate ecosystems Other ex-amples of resource problems in desert areas include overhunting of native ungulates for animal products such as tusks

Natural Resources Deserts of the world hold most of the reserves of oil, natural gas, and coal, and they therefore serve as a source of natural wealth for many countries in the Middle East These resources remained sufficient to supply energy needs into the twenty-first century, but with escalating costs, alternative energy sources will

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become more important Deserts also provide other

minerals, such as silver, lead, diamonds (in southern

Africa), and copper, but many deserts such as the

Sa-hara are not important for mineral resources

Desert plants are also used as food by many native

people In the southwestern United States, American

Indians used cactus fruits as a staple food In the Sahel

in northern Africa, the following types of foods were

available in substantial quantities: rhizomes and

fleshy stems, the seeds of forbs, grass seeds, fruits,

ed-ible gums, and mannas Fibers from desert plants are

also used for basket weaving in many countries, and

plant pigments are used as natural dyes

Vegetational Dynamics

In desert regions of the United States and elsewhere,

shrubby plants are increasing at the expense of

grass-land Reasons for this change are not clear, but several

factors are probably important Some workers have

suggested that climatic changes have favored a shift

from grasses to shrubs Increased carbon dioxide

concentration of the atmosphere from burning fossil

fuels is one hypothesis Others insist that the

intro-duction of domestic livestock beginning in 1850

dis-rupted the ecological balance in favor of shrubs Lack

of fire to restrict development of shrubs in grassland

has also been advanced as a possible cause Several

studies in southwestern deserts in the United States

have shown that native mammals and rabbits can

ex-ert considerable influence on vegetation and can

re-duce grass cover and abundance It is possible that all

these factors, and probably others not considered,

have together been responsible for changes in desert

vegetation

Increases in shrubs, such as mesquite in the United

States, eventually alter nutrient distribution patterns

In relatively uniform grasslands, soil nutrients are

dis-tributed fairly evenly As shrubs such as mesquite

in-crease at the expense of grasses, however, the shrubs

are able to take up nutrients from a much larger

vol-ume of soil These nutrients then tend to become

con-centrated around the individual mesquite trees and

to form islands of nutrient concentration Interdune

areas often suffer soil loss through wind erosion, and

the soil accumulates around individual mesquite

plants If the soil is deep enough, mesquite dunes

eventually form Interdune areas with little surface

soil are deficient in nutrients, especially nitrogen, and

lack water-holding capacity These changes also affect

animal life Some animals, such as bannertailed

kan-garoo rats and pronghorn antelope, utilize grassland habitat and are favored by grassland Others, such as those that feed on mesquite (insects and arthropods), are favored by the mesquite dunelands

Mining for coal and other minerals often disturbs desert ecosystems Mines are limited in size and in the area affected, but they can leave conspicuous scars on the landscape, especially with deep open-pit mines The area disturbed by the mines can be restored, but restoration is difficult and expensive

Rex D Pieper

Further Reading Evenari, Michael, Imanuel Noy-Meir, and David W

Goodall, eds Hot Deserts and Arid Shrublands New

York: Elsevier, 1985

Goudie, Andrew Great Warm Deserts of the World: Land-scapes and Evolution New York: Oxford University

Press, 2002

Laity, Julie Deserts and Desert Environments Hoboken,

N.J.: Wiley-Blackwell, 2008

Quinn, Joyce Ann Desert Biomes Westport, Conn.:

Greenwood Press, 2009

Sowell, John Desert Ecology: An Introduction to Life in the Arid Southwest Salt Lake City: University of Utah

Press, 2001

Ward, David The Biology of Deserts New York: Oxford

University Press, 2009

West, Neil E., eds Temperate Deserts and Semi-Deserts.

New York: Elsevier Scientific, 1983

Web Site U.S Geological Survey Deserts: Geology and Resources http://pubs.usgs.gov/gip/deserts See also: Conservation; Desertification; Ecology; Ecosystems; Farmland; Geochemical cycles; Irriga-tion; Rangeland; Soil

Developing countries

Categories: Countries; social, economic, and political issues

Developing countries’ resources have helped to feed and fuel the world’s developed countries As the devel-oping countries themselves industrialize, and as their

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populations grow, the demands on these resources

in-crease, and the issues of resource constraints and

envi-ronmental degradation rise on the political agenda.

Background

Developing countries are a diverse group, with

tre-mendous variety in size, income, and industrial

devel-opment China and Singapore reflect the size

dispari-ties, with the former measuring about 9.6 million

square kilometers and the latter approximately 1,000

square kilometers Of the 210 countries the World

Bank categorizes as high, middle, or low income, 70

percent are classified as developing countries Of

these, 30 percent are categorized as low-income

coun-tries (with per capita earnings equivalent to $975 or

less) These include Bangladesh, Chad, and Ethiopia

The Bahamas, Cyprus, Kuwait, and Qatar are among

the 31 percent in the high-income category Although

many of these countries are still very dependent on

primary goods, a small number, including South

Ko-rea and Venezuela, have undergone significant

indus-trialization

Resource use in developing countries is

condi-tioned by a web of global, national, and local factors

The nature of their economies and their relative lack

of economic power combine to determine their

pat-tern of resource use This patpat-tern is closely associated

with the asymmetric economic relations between

de-veloping countries and industrialized countries

Con-sumption patterns in industrialized countries

high-light the variety of goods and services associated with

a consumer culture; conversely, in most developing

countries the focus is on basic needs Industrialized

countries are far greater consumers of commercial

energy resources such as oil, natural gas, and coal

De-veloping countries, however, consume more wood

and wood products, primarily as fuel wood and

char-coal, and clear more of their forests, primarily for

agri-culture Resource use patterns change over time: In

the past, industrialized countries engaged in

substan-tial deforestation, and as developing countries

indus-trialize during the twenty-first century, their use of

commercial energy sources will increase significantly

In their efforts to satisfy both the interests of the

in-dustrialized countries’ capital and their own needs,

some developing countries extend the boundaries of

their economies by exhausting soils, removing

old-growth forests, or overexploiting fisheries A

combi-nation of forces operate at the global, combi-national, and

local levels to shape policies regarding development,

trade, and investment—often with disastrous conse-quences for the environment

Local Factors Inequalities within the societies of developing coun-tries result in skewed patterns of access to land and other assets, with elites benefiting disproportionately For example, in South American countries, 17 per-cent of the landowners control 90 perper-cent of the land Short-term needs can force landless families to farm fragile mountain slopes and torch rain forests in or-der to plant foods In Brazil, poor people clear the for-ests to farm Because of the fragility of the soils, in a short time yields diminish, and farmers must move on

to other areas of rain forest Similar practices result in the depletion and degradation of freshwater re-sources, soils, forests, and habitats

The poor are both agents and victims of environ-mental degradation, whether it is a result of their own actions or a consequence of consumption by higher-income groups The poor have few or no alternatives when the environmental resources on which they depend are degraded Dwindling food supplies, un-safe drinking water, polluted air, and unsanitary conditions contribute significantly to reduced life ex-pectancy and high child mortality Moreover, long-standing traditional social and economic patterns encourage poor Third World people to have many children The result is a vicious cycle: A large popula-tion leads to more poverty and increasingly threatens the renewable resources on which local populations depend

Thus, development and environment are inextri-cably linked: Development that alleviates poverty is essential if renewable resources are to be preserved

in developing nations, and material redistribution is necessary For sustainable use of natural resources to

be feasible, people need to have some measure of con-trol of, and access to, resources Case studies indicate that small holders who own their land tend to take care of it, unlike squatters and tenant farmers, who tend to deplete soils, forests, and water resources more rapidly because they assume or fear they will lose access to them

National Factors Problems at the local level are often reinforced by national policies that neglect or discriminate against the poorer members of society, with negative conse-quences for the environment For example, tax laws

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may favor the rich, or the structure of development

in-vestment may favor urban areas Sometimes farmland

near cities is taxed at its development value rather

than as agricultural land As a consequence, poor

farmers who cannot afford the higher taxes are forced

off the land In addition, government enactments

in-tended to manage common property resources can

have negative effects on both the poor and the

envi-ronment For example, in a number of West African

countries, colonial and subsequent governments

claimed all the trees as their own Farmers could cut

them only after a laborious permit process, and

cer-tain species could not be cut at all While this slowed

the process of deforestation, it also dissuaded farmers

from planting trees Recently, this practice has been

reversed, and countries such as Burkina Faso, Mali,

and Niger are encouraging farmers to mix trees and

crops, an ancient farming practice in West Africa

Governments have also been slow to implement

adequate land-planning policies and environmental

impact assessment In many Caribbean states,

envi-ronmental legislation is fragmented into several

dis-parate regulations, and responsibility for its

admin-istration is distributed among various departments

As a consequence, developing countries are

repeat-ing some of the environmental problems associated

with the industrialized countries, such as air and water

pollution, toxic emissions, and waste disposal

prob-lems

Global Factors

Global factors combine with local and national factors

to exacerbate unsustainable resource-use patterns At

the global level, developing countries’ options are

constrained by a number of interrelated forces, such

as declining terms of trade, oppressive debt burdens,

and inappropriate investment strategies These forces

have significant consequences for resource

consump-tion

With their dependence on primary products,

de-veloping countries are often among the losers when

trading systems are liberalized The market prices of

primary products have fallen rapidly, while the prices

of the manufactured goods that they import have

risen significantly In the effort to make up such

finan-cial shortfalls, developing countries may feel forced to

tap their natural resources more extensively

One result of a focus on free trade, with its

empha-sis on growth, is the exploitation of natural resources

for short-term profit This exploitation may mean the

clearing of rain forests for cattle ranching or the shift-ing of agricultural land from domestic food produc-tion to export crops In addiproduc-tion, environmental stan-dards and resource regulations can be challenged as barriers to trade Regulations produced by the North American Free Trade Agreement (NAFTA) and the General Agreement on Tariffs and Trade (GATT) are illustrative Under NAFTA, each country has to pro-vide other parties with the same access to its resources that it provides to its own citizens and other domestic parties The Uruguay Round of GATT resulted in some provisions with direct implications for environ-mental regulations One of GATT’s objectives is to limit most restrictions on trade: Therefore GATT can

be used to challenge the rights of nations to use im-port and exim-port controls to conserve threatened re-sources such as forests and fisheries The new trade provisions also discourage the use of strong environ-mental provisions by states, because these could be judged as being in violation of GATT rules These reg-ulations work against the concept and practice of sus-tainable use of resources

International institutions, such as the World Bank and the International Monetary Fund (IMF), encour-age export-led development as a priority, but this export-led strategy has reduced many countries’ ca-pacity to address their environmental problems The World Bank, as the principal single source of funding for Third World development, can have a profound impact on environmental policy in developing coun-tries Its development model has emphasized large-scale schemes dealing with water management, power generation, and transport infrastructure Many of these projects have resulted in serious disruptions of local ecosystems, in environmental stress, and in the displacement of thousands of people The World Bank, and the other multilateral development banks, such as the InterAmerican Development Bank, the Asian Development Bank, and the African Develop-ment Bank, allocate more than one-half of their proj-ect loans to areas that can have marked effproj-ects on the environment, including agriculture, rural develop-ment, dams, and irrigation schemes Oversight of the projects’ environmental consequences is inadequate IMF policy has also had significant environmental consequences for developing countries The IMF has responded to the Third World debt problem by re-quiring the countries to adopt structural adjustment programs These programs include a wide range of policy measures intended to restore creditworthiness:

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cuts in government expenditures, reduction or

elimi-nation of subsidies, currency devaluation, and

reduc-tion of trade barriers The intent of these programs is

to increase foreign exchange earnings so that the

countries can make debt payments However,

struc-tural adjustment can have disastrous impacts on the

environment The emphasis on boosting exports to

earn foreign exchange can result in the destruction

of natural resources such as forests, wetlands, and

mangroves and in the excessive development of

eco-logically damaging industries such as mining The

pressure for countries to reduce government

expen-ditures drastically can cause the elimination or

post-ponement of programs to manage wildlife or enforce

environmental laws Additionally, structural

adjust-ment programs that hurt the poor will often also hurt

the environment: As a last resort, unemployed people

might farm fragile hillsides or engage in

slash-and-burn agriculture in forest areas

In recent decades, some developing countries have

experienced more rapid economic growth than

in-dustrialized countries have In part, their growth

re-flects an increasing transfer of basic production to

developing countries and the expansion of

manufac-turing there These shifts create additional economic

value and employment, but they also increase the

en-vironmental burden Corporations are shifting

com-plete industrial operations to the Third World The

end products are then shipped back to the developed

country, where consumers get the benefit of the

prod-uct while shifting the environmental costs of

produc-tion to others For example, there has been a

signifi-cant shift of plant investment for organochloride

manufacture to the developing world In the 1980’s

and 1990’s, U.S companies relocated more than two

thousand factories to Mexico, where enforcement of

environmental laws is minimal

Transnational corporations play a major role in

this industrial transition These corporations are the

principal beneficiaries of a liberalized trading system

Because they control the bulk of world trade and

in-vestment, they are major environmental actors They

can affect the environment in Third World countries,

both directly and indirectly In order to attract

invest-ment from these corporations, a Third World country

might adopt inadequate environmental regulations

or might choose not to enforce existing laws Virtually

all commercial enterprises have direct environmental

consequences because of process and product

pollu-tion The former includes pollution generated by the

chemical, iron and steel, petroleum, and paper indus-tries The latter variety is found in agriculture Because agriculture is the primary economic sec-tor for many developing countries, examining trans-national agribusiness is important Agribusiness in-terests have made alliances with research institutes, agricultural colleges, regulatory agencies, government ministries, and aid agencies These relationships en-able them to shape agricultural practices and policies significantly Their practices usually reflect a cost-ben-efit analysis that marginalizes environmental costs Corporate policy can have negative consequences for resources such as land, forests, and water Transna-tionals control 80 percent of the land used for export crops worldwide This fact is reflected in land-use pat-terns in countries such as Brazil and India In Brazil, corporations own more land than is owned by all the peasants combined, and in India, some of the more wealthy farmers grow maize and sunflowers for Cargill and tomatoes and potatoes for Pepsi Corporations specialize in monoculture, with heavy use of chemical fertilizers and pesticides With the focus on produc-tion for export, developing countries become depen-dent on food imports This focus has also aided in the destruction of tropical rain forests More than one-quarter of Central America’s rain forest has been turned to grass for cattle ranching Almost all the beef raised has been exported In the 1970’s, beef produc-tion in Latin America attracted more than $10 billion from the World Bank and the InterAmerican Devel-opment Bank In Africa and Asia, corporations are also at work in the forests, but for timber rather than beef These activities have meant the destruction of ecosystems and a decrease in biodiversity

Prospects for Sustainable Development Sustainable development was a major agenda item at the 1992 Earth Summit in Rio de Janeiro Agenda 21, which was adopted at the conference, emphasized sustainable development and the provision of basic needs for the poor As global awareness of resource limits and environmental damage grow, developing countries are under increasing pressure to adjust rap-idly to environmental circumstances Developed countries have been the major contributors to com-mon property problems, such as ozone depletion and climate change, but they cannot address these prob-lems adequately without the cooperation of develop-ing countries As a result, developdevelop-ing countries are be-ing pressed to minimize their use of the processes and

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commodities that enriched the industrialized

coun-tries

During negotiations over environmental

manage-ment regimes, developing countries have been able

to bargain for some financial assistance to help them

make the transition to more sustainable processes

Still, this small fund will not have a major impact

on their transition to a more sustainable

consump-tion pattern Developing countries need to protect

their endangered renewable-resource base

Accom-plishing this will require reorienting development

to alleviate poverty and enable poor people to meet

their basic needs in ways that do not degrade water,

soil, and forest resources or reduce biodiversity This

task will be extremely difficult as long as large amounts

of their natural resources are owned or controlled by

foreign entities In the present global economic

con-text, many developing countries recognize only two

viable economic options: exploiting their natural

re-sources to the point of exhaustion or importing “dirty

industries.” Consequently, the structural inequities

that distort global and national societies and

econo-mies jeopardize the transition to sustainable

develop-ment If these inequities are not addressed,

sustain-able resource use will be an ever-receding mirage

Marian A L Miller

Further Reading

Ascher, William, and Robert Healy Natural Resource

Policymaking in Developing Countries: Environment,

Economic Growth, and Income Distribution Durham,

N.C.: Duke University Press, 1990

Barbier, Edward B Natural Resources and Economic

De-velopment New York: Cambridge University Press,

2005

Bonfiglioli, Angelo Lands of the Poor: Local

Environ-mental Governance and the Decentralized Management

of Natural Resources New York: United Nations

Cap-ital Development Fund, 2004

Dellink, Rob B., and Arjan Ruijs, eds Economics of

Pov-erty, Environment, and Natural-Resource Use New

York: Springer, 2008

Durning, Alan Thein Poverty and the Environment:

Re-versing the Downward Spiral Washington, D.C.:

Worldwatch Institute, 1989

Elliott, Jennifer A An Introduction to Sustainable

Devel-opment 3d ed New York: Routledge, 2006.

French, Hilary F Costly Tradeoffs: Reconciling Trade and

the Environment Edited by Ed Ayres Washington,

D.C.: Worldwatch Institute, 1993

Gupta, Avijit Ecology and Development in the Third World.

2d ed New York: Routledge, 1998

Miller, Marian A L The Third World in Global Environ-mental Politics Boulder, Colo.: Lynne Rienner, 1995 World Bank Poverty and the Environment: Understand-ing Linkages at the Household Level WashUnderstand-ington,

D.C.: World Bank, 2008

Web Site World Resources Institute World Resources 2008: Roots of Resilience— Growing the Wealth of the Poor

http://www.wri.org/publication/world-resources-2008-roots-of-resilience

See also: Agenda 21; Brazil; Capitalism and resource exploitation; China; Deforestation; Earth Summit; In-dia; Indonesia; Land ethic; Monoculture agriculture; Population growth; Rain forests; Resources as a source of international conflict; Slash-and-burn agri-culture; South Korea; World Bank; World Commis-sion on Environment and Development

Diamond

Category: Mineral and other nonliving resources

Diamond is one of the world’s most important minerals and gemstones; it is the element carbon (C) crystallized

in the isometric system.

Background Diamond is the hardest known substance, natural or artificial, and is number 10 on the Mohs hardness scale The close-packed cubic arrangement of the at-oms gives diamond its unique hardness It also has the highest thermal conductivity of any known substance Historical records of diamonds date back to 3000 b.c.e In recent centuries, Golconda diamonds of India dominated diamond production until the early eighteenth century In 1725, Brazilian diamond mines gained prominence South Africa’s “great diamond rush” began in 1867, and in 1890, the De Beers com-pany consolidated dozens of mining communities in Africa Diamond derives its name from the Greek

word adamas, which means “unconquerable.”

Almost all of the world’s diamond production comes from Africa, most notably South Africa Other

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diamond-producing countries include Angola,

Bor-neo, Ghana, Guyana, Namibia, Sierra Leone,

Tanza-nia, Venezuela, Congo, Brazil, and Russia (Siberia)

In the United States diamonds have been found in

Ar-izona, Arkansas, Montana, and Nevada

Technical Definition

The atomic number of carbon is 6, and its atomic

weight is 12.011 It belongs to Group IVA of the

peri-odic table of elements Gem diamonds have a density

of 3.52, although “black diamonds” have a density of

about 3.15 Diamond slowly burns to carbon dioxide

at a very low temperature (900° Celsius)

Diamond’s high refractive index (2.417) and

strong dispersion property (0.058) guarantee its

su-premacy as a gemstone However, only about one-fifth

of all the diamonds mined qualify as gems Most of

the remaining uncut diamonds are used by industry

Tunnel boring and oil-well drilling equipment uses

diamond-studded rotary bits Carbide grinding wheels,

abrasion-resistant cutting tools, and glass-etching and

glass-cutting equipment use industrial-quality

dia-monds Some dentists and surgeons use

diamond-headed scalpels to cut delicate bones and tissue

Diamond coatings are used in integrated circuits,

prosthetic devices, and biosensors Diamond is the most important industrial abrasive, and industry uses about 80 percent (by weight) of all diamonds pro-duced However, this represents only about 30 per-cent by value

Creation and Properties of Diamond About 30 meters inside the Earth, exceedingly high pressures and temperatures (more than 1,400° Cel-sius) cause magnesium-rich rock melts to crystallize, resulting in the formation of diamonds Samples of deep mantle material contain diamonds as a natural component The reaction of groundwater with hot, magnesium-rich, deep mantle material aided by car-bon dioxide leads to the formation of a rock called kimberlite Kimberlite is an igneous rock that is ultrabasic and contains very little silica Kimberlite is the world’s principal source of diamonds Explosive eruptions create craters filled with deep mantle rock formations and permit diamond-containing rocks

to surface through cracks These are known as dia-mond pipes (sometimes incorrectly called “volcanic necks”)

In addition to being the hardest substance, mond is an excellent conductor of heat Because

dia-Data from the U.S Geological Survey, U.S Government Printing Office, 2009.

18,000,000 8,000,000

1,000,000

23,000,000 15,000,000

9,000,000

3,000,000

Carats

25,000,000 20,000,000

15,000,000 10,000,000

5,000,000

Congo, Democratic

Republic of the

China

Botswana

Australia

Russia

South Africa

Other countries

23,000,000 Industrial Diamonds: World Mine Production, 2008

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monds possess the highest thermal conductivity of

any known substance, industrial-quality diamonds are

used in abrasion-resistant cutting tools Almost all

dia-monds are nonconductors of electricity However,

some diamonds permit the passage of electric current

when bombarded with radiation Diamond crystals

form as octahedrons, dodecahedrons, and cubes A

well cut gem can reflect almost all the light that it

re-ceives This quality is called “luster.” In addition, it can

disperse or separate the colors of the spectrum while

reflecting the incident light This quality is called

“fire.”

Occurrence of Diamond

Mining experts have discovered hundreds of

diamond-containing dikes and pipes in Transvaal, Kimberley

District, and Free State (formerly Orange Free State), South Africa; Yakutsk, Siberia; Shinyanga, Tanzania; Mbuji-Mayi, Democratic Republic of the Congo; Yengema, Sierra Leone; Murfreesboro, Arkansas; and several other locations However, it is not economi-cally feasible to carry out “mine-at-depth” procedures

in most of these pipe mines Unless new pipes are dis-covered, natural diamonds may be exhausted rela-tively soon

The erosion of diamond pipes over millions of years has resulted in secondary deposits called alluvial

or placer deposits These deposits contribute signifi-cantly to the world’s total diamond production Most alluvial diamonds are recovered from stream gravel, but beach gravel is also a good source Diamond-containing beach gravel extends to the depths of

These miners, photographed around 1905, and others worked the dozens of South African mines owned by Cecil Rhodes’s De Beers Consoli-dated Mines Until 1891 the company controlled 90 percent of the world’s diamond production (Library of Congress)

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the ocean floor, although there is no economical

means of recovering diamonds from ocean depths

Diamonds are also found in glacial tills Minute

quan-tities of microscopic diamonds have been found in

meteorites as well

Synthetic Diamonds

On February, 15, 1955, the General Electric Company

announced its success in creating a synthetic

dia-mond Since then synthetic diamonds have become

widely used in grinding wheels and a number of other

applications They are normally single crystals,

usu-ally octahedral in shape Since they have several

cut-ting edges, they are preferred over natural diamonds

for industrial purposes To make them, graphite

(an-other form of crystalline carbon) is subjected to very

high temperatures and pressures Extreme pressures

as high as 296,076 atmospheres (about 30 billion

pas-cals) and temperatures as high as 3,037° Celsius (water

boils at 100° Celsius) have been used, depending

upon the actual process Two common proce-dures are shock conversion and static conver-sion Synthetic diamonds are also manufac-tured by the static crystallization of certain alloys and molten metals

Synthetic diamonds, normally black in color, are produced in grain sizes that are about one-hundredths of a centimeter in diameter It is possible to “grow” larger, gem-quality synthetic diamonds, but the process is too costly to be feasible Synthetic diamonds are chemically and crystallographically identical to the natu-rally occurring diamond gemstone “Imitation diamonds,” on the other hand, are completely different from either synthetic or genuine dia-monds Imitation diamonds do not possess either the hardness or the crystallographic structure of the genuine diamond; they are chemically different They are made of glass or other material and are simply intended to imi-tate the appearance of a diamond

Cutting Diamond After mining and recovery, gem-quality dia-monds are separated from industrial-quality ones A rough, uncut diamond looks like a dull piece of glass Precise cutting, artful grinding, and skillful polishing of the diamonds yield outstanding gems, and some have attained his-toric fame Diamond cutting began in India and was later perfected in Italy Only a diamond can cut a diamond: Diamond crystals are cut, cleaved, shaped, and polished by “diamond dust on a lap.” World-famous diamond cutting establishments are concentrated in Antwerp, Belgium, and in Amster-dam, the Netherlands India and Israel have also emerged as world leaders in diamond cutting The most popular cut is the “brilliant cut,” which has a round shape with fifty-eight facets Gem-quality dia-monds are classified according to their weight, clarity, color, and absence of flaws The weight of a diamond

is measured in carats; a carat equals 0.2 gram, or about 0.00704 ounce Transparent, colorless, and light blue diamonds are extremely rare and are considered to

be highly valuable gems There are red, pink, blue, and green diamonds Diamonds with a yellow tint are more common As the tint becomes increasingly yellowish, the value decreases Industrial-quality diamonds are gray, brown, or black and are almost opaque They are gems of poor quality

Machinery manufacturing 32%

Mineral exploration 18%

Stone &

ceramic production 22.5%

Construction

14.5%

Transportation

8.5%

Other 4.5%

Source:

Historical Statistics for Mineral and Material Commodities in the United States

U.S Geological Survey, 2005, industrial diamond statistics,

in T D Kelly and G R Matos, comps.,

, U.S.

Geological Survey Data Series 140 Available online at

http://pubs.usgs.gov/ds/2005/140/.

U.S End Uses of Industrial Diamond

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Famous Diamonds

The largest diamond ever found, the Cullinan, was

found in 1905 in the Premier Mine, Transvaal, South

Africa, and weighed 3,106 carats This stone was cut

and polished into several gems, two of them world

fa-mous: The 530-carat Star of Africa and the 309-carat

Star of Africa II are among the British crown jewels,

housed in the Tower of London These are the world’s

largest cut diamonds The cutting of the Cullinan

also resulted in another seven large gems and ninety

smaller ones

The 109-carat Koh-i-Noor (“mountain of light”),

set in the British crown itself, is the oldest diamond

gemstone known to historians; its history has been

traced back to 1304 This diamond had its origin in

In-dia, and it originally weighed 186 carats before Queen

Victoria had it recut in 1852 Many believe that the

largest blue diamond, the 44.5-carat Hope diamond,

presently in the Smithsonian Institution, adorned

the eye of an Indian god Other world-famous

dia-monds India has contributed include the Regent or

Pitt (140 carats, presently in the Louvre, France); the

Orlov (200 carats, presently in Russia); the Florentine

(137 carats, location unknown); and the Great Mogul

(280 carats, location also unknown)

Mysore Narayanan

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