DK - WOW! The Visual Encyclopedia of Everything

170

Metals are minerals with a closely packed atomic structure, which

makes them excellent conductors of electricity and heat. Most are

also strong, workable materials, ideal for making a huge range

of artefacts. Pure metals are elements, with only one type of

atom in their chemical structure. In nature, many are

mixed with rocks, or combined with other elements

to form chemical compounds. These ores must be

mined and processed to extract the pure metals.

Metals

SILVER ▲

One of the most prized metals, silver occurs

in pure “native” form in volcanic rocks. It

is very shiny when polished, but soon

tarnishes. Since it is quite soft, it

is often mixed with other metals

to make harder alloys such

as sterling silver.

Native

silver

Galena

(lead ore)

Lead scuba weights

Sterling silver flute

Gold audio connectors

Copper

pipes and

wires

Tin can

A deep-sea

submersible

◀ LEAD

Very dense and heavy,

lead is a dark, soft metal

with a low melting point,

which makes it easy to shape. It is

widely used in lead-acid car batteries,

but also for heavy weights and roofing.

The main lead ore is galena, a compound

of lead and sulfur that forms big crystals.

▼ COPPER

Copper is a soft metal, often alloyed

with zinc to make brass, or with tin

to form bronze – both much harder.

A good conductor, it is widely

used for electric wire. Its main

ore is chalcopyrite, a compound

of copper, iron, and sulfur.

◀ PLATINUM

A beautiful, very heavy metal,

platinum is often used in jewellery

because, like gold, it never tarnishes.

It is tougher than gold, and rarer,

so it is more precious. It is sometimes

found as nuggets of pure metal.

▼ GOLD

Easily worked, always shiny, and the

only metal that is always found in

pure form, gold has been used

to make precious objects for

thousands of years. It is also

used to make electrical

contacts that do not

degrade by tarnishing.

Chalcopyrite

(copper ore)

Platin

um

Plat

inu

m

(^) ri
ng
The nickel in the stainless
steel makes this hip joint
corrosion-proof

G

arn

ier

ite

(n

ick

el

o

re

)

Gold nugget

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