Electrical Conductivity
Also: Conductivity, Specific conductivity, Electrical conductance
Electrical conductivity describes how well a material carries an electric current and, for precious metals, is a key quality criterion in industrial applications.
Electrical conductivity (symbol σ, unit siemens per metre, S/m) expresses how readily electric charge carriers — in metals these are freely moving electrons — can flow through a material. The higher the value, the lower the resistance the material puts up against the current. For silver and copper this property is of outstanding industrial importance.
The physics behind it
The reciprocal of conductivity is the specific electrical resistivity ρ (unit ohm-metre, Ω·m). The two quantities are linked by:
σ = 1 / ρ
Within a metal the conduction electrons are scattered by the crystal lattice. Higher temperature, lattice defects and foreign atoms (alloying constituents) all intensify that scattering and lower the conductivity. A pure, single-crystal metal therefore always conducts better than an alloy built on the same parent metal.
Conductivity of the main precious metals compared
| Metal | σ (× 10⁶ S/m) | Rank | Typical use |
|---|---|---|---|
| Silver (Ag) | 63.0 | 1 (of all metals) | Conductive traces, contacts, solar cells |
| Copper (Cu) | 59.6 | 2 | Cabling, circuits, transformers |
| Gold (Au) | 45.2 | 3 | Connectors, bond wires, microprocessors |
| Aluminium (Al) | 37.7 | – | High-voltage transmission lines |
| Palladium (Pd) | 9.5 | – | Connector contacts, catalysts |
| Platinum (Pt) | 9.4 | – | Temperature sensors (PT100/PT1000) |
Silver tops the table for every metal — a fact that helps underpin the silver price through industrial demand. Copper, despite a slightly lower conductivity, is the most widely used conductor because it is considerably cheaper and far more abundant. Gold's appeal in electronics is not peak conductivity but its exceptional corrosion resistance: gold-plated contacts do not oxidise and stay reliable indefinitely.
The influence of temperature and alloying
- Temperature dependence: metals conduct less well as they warm up (positive temperature coefficient). At 0 °C copper's conductivity is roughly 12% higher than at 25 °C.
- Alloying effect: sterling silver (92.5% Ag, 7.5% Cu) conducts about 55% less well than pure silver (around 28 instead of 62 MS/m). For high-precision conductive tracks, fine silver (999 or better) is therefore preferred.
- Cryogenic range: many metals become superconducting at very low temperatures (σ → ∞), but gold and copper do not — they remain ordinary conductors.
Significance for industry and the precious-metals market
Around half of global silver demand is accounted for by industrial applications, including photovoltaic silver paste, solders and electrical contacts. This baseline demand gives the silver price a steady industrial component that is largely independent of investment sentiment. Gold is used as a thin film (bond wires, connectors) in the semiconductor industry precisely because its oxidation protection stays dependable over decades.
You can work out the current melt value of your silver or gold holdings with our Melt Value Calculator.
In brief
Silver is the most electrically conductive of all metals and therefore plays a pivotal role in the electronics and solar industries. Gold excels in high-reliability applications through its freedom from oxidation rather than peak conductivity. Conductivity falls as temperature rises and with every alloying addition — electrically, purity pays off.