Tarnish-Resistant Alloys: Tarnish-Resistant Doesn’t Mean Tarnish-Proof!
With all of the considerable advances that science makes possible – from artificial organs to space travel – it’s surprising that the formula for a tarnish-proof sterling silver alloy remains a mystery.
“Many people are wary of buying silver as tarnishing is always a problem, and they know from experience that eventually it will turn a darkish dull shade of yellow, brown and even black,” said Dippal Machanda, technical director of Assay Office Birmingham (an institution that tests the purity of precious metals).
Labs have often been hampered by the fact that legally, standard sterling silver alloy must contain 925/1000 pure silver. This leaves only 75/1000 of space for other metals to provide tarnish protection. This 75/1000 can be made up of:
These substances can be combined together in a variety of ratios, and they provide oxidation, a layer of oxide that prevents sulfur from reacting negatively with the silver. For this reason, quantitative research demonstrates that many of these alloys are indeed more resistant than traditional silver alloys.
But has any lab succeeded in creating a completely anti-tarnish formula for silver? Some commercial enterprises may claim that they’re coming close.
However, in a scientific assessment of the properties of these alloys, Machanda had this to say:
“To date no one has come up with a guaranteed completely tarnish-resistant silver alloy suitable for jewelry. The researchers continue to apply their knowledge of science to fight against nature.”
Machanda’s statement emphasizes the inherent difficulty in attempting to prevent silver jewelry from tarnishing – it’s a literal fight against nature and the natural properties of silver. Fortunately, there are a number of easy and inexpensive options to maintain the luster and shine of silver jewelry without altering its natural properties.