The question of whether gold is more durable than silver is complex because “durability” applies to two properties: physical resistance to wear and chemical resistance to the environment. Pure gold and pure silver are both relatively soft and highly malleable, meaning they can be easily dented or scratched. Their chemical reactions to air, moisture, and common substances are vastly different, which is the primary factor in their long-term endurance. Ultimately, the real-world durability of both metals is determined not by their pure form but by the other metals mixed with them.
Comparing Mechanical Hardness and Malleability
In their pure forms, both gold and silver are extremely soft metals, which is why they are rarely used for items requiring physical strength, such as jewelry. The Mohs scale of mineral hardness, which measures resistance to scratching, rates pure gold at about 2.5, and pure silver falls within the 2.5 to 3 range. This score means both metals are easily scratched by common items like a fingernail or a copper coin.
Gold is the most malleable metal, meaning it can be hammered into extremely thin sheets without cracking; silver also possesses high ductility. This malleability makes both metals prone to deformation, especially in delicate designs or areas of high friction. Gold is significantly denser than silver (19.32 g/cm³ compared to 10.49 g/cm³). While this higher density might offer slight resistance to minor denting, both pure metals lack the physical hardness needed for longevity in daily use.
Chemical Stability and Resistance to Tarnish
The most significant difference in durability lies in their chemical stability. Gold is classified as a noble metal, meaning it is highly inert and resists chemical reactions with most environmental factors. Pure gold does not react with oxygen, moisture, or sulfur compounds in the air, so it does not tarnish or rust over time. This chemical non-reactivity gives gold superior long-term durability against corrosion and discoloration.
Silver, in contrast, is highly reactive to sulfur compounds naturally present in the atmosphere and in common household items. This reaction forms a layer of silver sulfide on the surface, known as tarnish. While tarnish does not typically affect the metal’s structural integrity, it rapidly diminishes its aesthetic quality and requires frequent cleaning. Therefore, gold is substantially more resilient than silver in terms of chemical durability against environmental exposure.
How Alloying Determines Real-World Durability
For practical applications, both gold and silver are almost always alloyed—mixed with other metals—to increase their physical durability. Gold purity is measured in karats, and alloying with metals like copper, silver, or zinc drastically increases its physical hardness. For example, 14-karat gold is 58.3% pure gold; the substantial percentage of alloy metals makes it much stronger and more resistant to scratching than 24-karat gold. However, as the karat drops, the gold’s chemical durability slightly decreases because the non-gold alloy metals can be susceptible to tarnish or corrosion.
Silver is typically alloyed to create sterling silver, which consists of 92.5% pure silver and 7.5% other metals, most commonly copper. This addition significantly improves the metal’s physical hardness and tensile strength, making it suitable for jewelry and tableware. Despite the improved physical strength, the copper content in sterling silver is the reason it still tarnishes easily when exposed to air and moisture. Gold remains chemically more durable, while the physical strength of both metals depends on the specific alloy mixture used.