Silver has the highest electrical conductivity of all metals. In fact silver defines conductivity - all other metals are compared against it.

Silver possesses the unique ability to not spark, making its use in electrical contacts irreplaceable. Pure silver has the highest electrical and thermal conductivity of all metals, and possesses the lowest contact resistance.
Silver has the unique ability to "wet" (join) many metals. It is this quality that consumes silver in many soldering and brazing applications. Silver is replacing tin/lead solders in many applications -- for its higher conductivity and to eliminate the use of lead for environmental reasons.

Lesser known facts about Silver

One of the most fascinating properties of silver is its bactericidal quality. Small concentrations of silver or silver salts kill bacteria by chemically affecting the cell membranes, causing them to break down. Bacteria do not develop resistance to silver, as they do to many antibiotics. Because of its bactericidal properties, silver nitrate drops are used to clean the eyes of newborns in much of the world. Silver rich creams are common household ointments for burns. Cotton gauze soaked in silver solution is proving a miracle cure for intensive care burn victims. While silver keeps bacteria at bay, it also cauterises minor capillaries, preventing blood loss, and the build-up of excessive scar tissue. Silver gauze is used to pack wounds of patients during transport to medical facilities. It is relatively inert in the human body, so it is commonly used to pin fractured bones, and sew large wounds. Silver-based water purification systems, both portable and industrial, are gaining widespread popularity.

The total allowable impurities in 99.9% (.999 fine) silver is 1000 ppm or 1 part in 1000. These impurities and their maximums are 1) Copper, 800 ppm, 2) Lead, 250 ppm, 3) Iron, 200 ppm, and 4) Bismuth, 10 ppm. This product is readily available in wire form and costs about $3.00 above the market (spot) price of silver. When this product is used to make electro-colloidal silver at a concentration of 5 ppm, the total impurities from the silver drop to 4 ppb (parts per billion) copper, 1.25 ppb lead, 1 ppb iron, .05 ppb bismuth. With all allowable impurities at these low levels, there is a reasonable argument for not being concerned. Still, sometimes small things make a big difference. 99.99% silver (.9999 fine) has total allowable impurities of 100 ppm of the same metals in the same ratios, and costs (in wire form) between $50-$90 above the spot price of silver. 99.999% silver (.99999 fine) has total allowable impurities of 10 ppm, and in wire form costs about $250 above the spot price. 99.9999% silver, in wire form, costs more than gold and is very difficult to find commercially.

Silver has a pure sweet acoustic resonance, better than any other metal, and is preferred by musicians for making high quality silver bells and musical instruments.

Silver is the whitest of all metals. This property, and its high reflectivity, was responsible for its Latin name argentum (white and shining), from which the chemical symbol for silver, Ag, is derived. Because it does not readily oxidize, silver can be found in the native state - in metallic form rather than as a compound - and can therefore be assumed to be one of the first metals discovered. It has been found in tombs dating from 4000 BC. Silver conducts heat and electricity better than any other metal does. It is second only to gold in ductility (the ability to be drawn out into fine wires) and malleability (the ability to be hammered into various shapes). Silver, like gold, does not react chemically with most substances. However, the presence of sulfur compounds causes silver to develop a black or gray coating of silver sulfide called tarnish. Because polluted air contains these compounds, silver tarnishing is a greater problem today than in the past.
Silver will carry high current loads without excessive heating when circuits are closed because of silver's high electrical conductivity. The arc energy of the circuit is dissipated without excessive temperature increase or detrimental effect on the silver contact due to the high thermal conductivity of silver.
The platinum family (platinum, palladium, ruthenium, iridium, osmium and rhodium) is one of the most important to the contact user. These materials and their alloys display exceptional qualities as they have high corrosion resistance, high resistance to arc erosion and a high melting point. The alloys of this family are very hard. Hence, they have good mechanical wear ability. When used in the proper applications, the platinum metals provide years of successful operation, but they have their limits. Due to fairly low conductivity, these materials are limited to light current applications, usually under five amperes. Another consideration is their cost, which is relatively high in comparison with silver base materials. To secure a reasonable cost relationship, these materials are normally furnished as composite contacts with a nickel-plated backing.

Electrical conductivity of some common metals, high lighted in red are some used in the Audio cable and connector industry. Interesting is that Aluminium has rating not far off that of Gold and hugely better than Platinum/Rhodium.

2 - Eddy Current Testing Manual on Eddy Current Method

RESIS. COND,/

SOURCE

ohm-m

SEIMENS

% IACS

CODE

MATERIAL

7.184E-08

1.392E+07

24.00

2

Admiralty Brass

7.009E-08

1.427E+07

24.60

1

Admiralty Metal (annealed

2.871E-08

3.483E+07

60.00 - 60.10

3

Aluminum Alloy, 7072

2.655E-08

3.767E+07

64.94

1

Aluminum, 99.99%

1.449E-07

6.902E+06

11.90

1

Antimonial Tin Solder

2.188E-07

4.570E+06

7.88

1

Antimonial Lead, 1% (Quenched and Aged)

3.918E-07

2.552E+06

4.40

1

Antimony

8.210E-08

1.218E+07

21.00

1

Beryllium Copper, Cond. At

4.000E-08

2.500E+07

43.10

1

Beryllium

7.184E-08

1.392E+07

24.00

2

Brass, Admiralty

3.918E-08

2.552E+07

44.00

1

Bronze, Commercial (Annealed)

6.842E-08

1.462E+07

25.20

1

Cadmium

3.540E-08

2.825E+07

48.70

1

Calcium

6.158E-08

1.624E+07

28.00

1

Cartridge Brass (Annealed)

1.959E-07

5.104E+06

8.80

1

Chromium

6.247E-08

1.601E+07

27.60

1

Cobalt

1.306E-07

7.656E+06

13.20

1

Columbium

1.014E-07

9.860E+06

17.00

1

Copper Beryllium, Cond. "A"

8.210E-08

1.218E+07

21.00

1

Copper Beryllium, Cond. At

2.028E-08

4.930E+07

85.00

1

Copper, Deoxidized (Annealed)

.707E-08

5.858E+07

101.00

1

Copper, Electrolytic Tough Pitch (Annealed)

1.664E-08

6.009E+07

103.60

1

Copper, Pure

1.724E-08

5.800E+07

100.00

2

Copper, Pure

3.831E-07

2.610E+06

4.50

2

Copper 70%, Nickel 30%

1.771E-07

5.647E+06

9.74

4

Copper 90%, Nickel 10%

3.748E-07

2.668E+06

4.60

1

Cupro - Nickel 30%

3.079E-08

3.248E+07

56.00

1

Gilding Metal (Annealed)

2.349E-08

4.257E+07

73.40

1

Gold

2.463E-08

4.060E+07

70.00

2

Gold, Pure

1.105E-07

9.048E+06

15.60

1

Ingot Iron (99.9% Fe)

5.289E-08

1.891E+07

32.60

1

Iridium

4.105E-08

2.436E+07

42.00

1

Leaded Commercial Bronze

8.535E-08

1.172E+07

20.20

1

Lithium

4.467E-08

2.239E+07

38.60

1

Magnesium, Pure

7.184E-08

1.392E+07

24.00

1

Manganese Bronze (Annealed)

5.225E-08

1.914E+07

33.00

1

Molybdenum

6.158E-08

1.624E+07

28.00

1

Muntz Metal (Annealed

3.831E-07

2.610E+06

4.50

2

Nickel 30%, Copper 70%

9.579E-08

1.044E+07

18.00

1

Nickel "A"

3.592E-08

2.784E+07

48.00

1

Phos. Bronze, 1.25% Phos. Grade E

1.059E-07

9.442E+06

16.28

1

Platinum

1.486E-07

6.728E+06

11.60

1

Platinum, Commercial

1.895E-07

5.278E+06

9.10

1

Platinum - Iridium Alloys

3.316E-07

3.016E+06

5.20

1

Platinum - Iridium Alloys, 18% Nickel Silver Alloy B

2.330E-07

4.292E+06

7.40

1

Platinum - Nickel Alloys

1.268E-07

7.888E+06

13.60

1

Platinum - Nickel Alloys

4.310E-07

2.320E+06

4.00

1

Platinum - Ruthenium (Contact Grade)

3.135E-07

3.190E+06

5.50

1

Platinum - Ruthenium (Jewelry Grade)

4.490E-08

2.227E+07

38.40

1

Rhodium

7.595E-08

1.317E+07

22.70

1

Ruthenium

4.310E-07

2.320E+06

4.00

1

Ruthenium - Platinum (Contact Grade)

3.135E-07

3.190E+06

5.50

1

Ruthenium - Platinum (Jewelry Grade)

1.197E-07

8.352E+06

14.40

1

Selenium

2.463E-07

4.060E+06

7.00

1

Silicon Bronze, Type A (Annealed)

1.437E-07

6.960E+06

12.00

1

Silicon Bronze, Type B (Annealed)

1.642E-08

6.090E+07

105.00

2

Silver, Pure