Sterling silver is a metal alloy used in jewelry and decorative arts, valued for its balance of beauty and strength. It is composed of 92.5% pure silver (Ag) and 7.5% of other metals, most often copper. Malleability is the ability of a metal to be permanently deformed—hammered, pressed, or rolled into new shapes without fracturing or cracking. This characteristic is fundamental to jewelry making, and sterling silver possesses it to a high degree.
The Malleability of Sterling Silver
Sterling silver is highly malleable, a property it inherits from its primary component, pure silver (fine silver). Pure silver is one of the most malleable metals, second only to gold. The metallic bonds within the silver crystal lattice allow the atoms to slide past one another under compressive stress, permitting the metal to deform without breaking apart.
This inherent softness and ductility mean that sterling silver can be rolled into thin sheets or drawn into fine wires, forms necessary for virtually all jewelry fabrication. The high silver content ensures the alloy retains much of this flexibility and workability. Although pure silver is even more malleable, it is too soft to maintain its shape for functional items and would easily bend and scratch with daily wear.
The Role of Copper in the Alloy
The 7.5% copper component is added to modify the physical properties of the soft silver. Copper atoms disrupt the uniform structure of the silver lattice, increasing the alloy’s overall hardness and tensile strength. This hardening prevents the finished piece from easily deforming or bending out of shape, a common issue with fine silver jewelry.
The addition of copper creates a functional trade-off, slightly reducing the malleability of pure silver but improving its durability for everyday use. This precise ratio ensures the metal is strong enough to hold intricate designs and resist wear, yet still retains enough workability for silversmiths to shape it.
Practical Applications in Craftsmanship
The malleability of sterling silver allows silversmiths to employ a wide range of complex metalworking techniques. The material can be subjected to repeated hammering, bending, and pressing without becoming brittle. Techniques like raising, where a flat sheet is hammered into a three-dimensional form, rely on the metal’s ability to be shaped under compressive force.
Detailed surface decoration techniques like chasing and repoussé are possible because the metal flows and displaces rather than tearing or cracking. Repoussé involves pushing the metal from the back to create a design in relief, while chasing refines the details from the front. Both techniques require high malleability to prevent fracturing under pressure.