Standard bullion silver bars are globally accepted, high-purity silver bars manufactured according to recognized bullion standards such as LBMA, COMEX, national mints, and accredited refineries. They are produced primarily for investment, institutional storage, exchange settlement, and industrial use.
Bullion silver bars may be cast or minted, but must always meet defined requirements for purity, weight accuracy, and permanent marking.
Bullion Standards & Grades
| Standard | Typical Weight | Purity |
|---|---|---|
| LBMA Good Delivery | ~30 kg (1,000 oz) | ≥ 99.9% |
| COMEX Deliverable | 1,000 oz | ≥ 99.9% |
| Retail Bullion Bars | 100 g – 1 kg | ≥ 99.9% |
| High-Purity Bars | Various | ≥ 99.99% |
✔ 999 fine silver is the global bullion minimum
✔ Each bar is individually assayed and marked
Chemical Composition
| Element | Typical Content |
|---|---|
| Silver (Ag) | 99.9 – 99.99% |
| Copper (Cu) | < 0.05% |
| Lead (Pb) | < 0.01% |
| Zinc (Zn) | Trace |
| Gold (Au) | ppm-level |
| Sulfur (S) | Trace |
Key Physical Properties
| Property | Typical Value |
|---|---|
| Density | 10.49 g/cm³ |
| Melting Point | 961.8 °C |
| Electrical Conductivity | ~105% IACS |
| Thermal Conductivity | ~430 W/m·K |
| Reflectivity | ~95% |
| Magnetic Behavior | Non-magnetic |
| Corrosion Resistance | Excellent (tarnishes in sulfur-rich air) |
Mechanical Properties
Standard bullion silver bars behave as near-pure silver; mechanical strength is secondary to purity and mass accuracy.
| Property | Cast Bars | Minted Bars |
|---|---|---|
| Hardness (HV) | 25 – 30 | 35 – 45 |
| Tensile Strength | ~170 MPa | ~200 MPa |
| Yield Strength | ~55 MPa | ~75 MPa |
| Elongation | 40 – 45% | 30 – 35% |
Metallurgical Characteristics
• Face-centered cubic (FCC) silver lattice
• Homogeneous single-phase Ag matrix
• Minimal segregation and excellent remelting behavior
✔ High ductility
✔ Stable microstructure at ambient temperature
Refining & Manufacturing Routes
Refining: Electrorefining, chemical purification, zone refining (ultra-pure)
Manufacturing:
• Cast bars: Melting, mold pouring, controlled cooling, stamping
• Minted bars: Billet casting, rolling, annealing, precision stamping
Available Forms & Sizes
Forms: Cast bars (rough surface), Minted bars (smooth finish)
Typical Weights:
• 10 g – 100 g (retail)
• 250 g – 1 kg (investment)
• 5 kg – 15 kg (institutional)
• 1,000 oz (exchange deliverable)
Applications
Investment: Wealth preservation, inflation hedge, portfolio diversification
Institutional: Central bank reserves, ETF backing, exchange settlement
Industrial: Electronics, solar cells, conductors, silver alloys
Advantages
✔ Globally recognized and liquid
✔ Consistent purity and weight
✔ Simple valuation based on spot price
✔ Fully recyclable and chemically stable
Limitations
⚠ Soft metal (easily scratched)
⚠ Tarnishes in sulfur environments
⚠ Large bars less divisible
⚠ Requires secure storage
Why Choose Standard Bullion Silver Bars
Standard bullion silver bars are chosen when maximum silver content, global tradability, and long-term value preservation are priorities. Their purity, liquidity, and universal acceptance make them the cornerstone of the global silver market.