Platinum Sterling, primarily used in jewelry, is a registered trademark of the American company called “American Bullion, Inc.” The name “Platinum Sterling” refers to more than one alloy of which the primary components are silver and platinum. “The range of Platinum Sterling alloys were developed in 2003 by Marc Robinson, and Chuck Bennett created the solder of the alloy” (Wikipedia).
The properties of Platinum Sterling…
“The platinum is used to replace at least some of the copper present in a typical sterling silver alloy provides a greater light reflectivity (by refining the grain structure) and resistance to tarnish (thought to be caused by oxidation of copper) than standard sterling silver which does not incorporate platinum. Platinum Sterling is a cheaper alternative to white gold. It is also hard wearing and very white so it does not require rhodium plating like white gold” (Wikipedia).
“Tests performed by the American Assay and Gemological Office showed that the whiteness of platinum-sterling alloys exceeds that of both sterling silver and white gold, with the new 3.5 percent platinum sterling displaying six times more resistant to tarnishing than standard sterling alloy” (Wikipedia).
The composition of Platinum Sterling…
“The composition of Platinum Silver is published; three alloys are commercially available, all containing standard .925 sterling silver and 1%, 3.5% or 5% platinum. A small amount of gallium can also be added to the composition to provide ease of manufacture of the alloy” (Wikipedia).
“The patent application for Platinum Sterling claims: A metal alloy having a composition consisting essentially of 90.5–95.5% silver by weight, about 0.5–6% platinum by weight, about 0.7–4% copper by weight, about 0.1–2% gallium by weight, about 1–3% tin by weight, about 1–2.5% germanium by weight, about 0.5–4% zinc by weight, and about 0.1–0.2% silicon by weight. And from the same claim: …the preferred embodiments of the present invention provide a metal alloy comprising about 90.5–95.5% silver, about 0.5–6% platinum, about 0.7–4% copper, and about 0.1–2% gallium. In some embodiments, the alloy further comprises about 0.5–4% zinc, about 0–0.2% silicon, about 0–0.3% boron and about 0–1.5% indium. In other embodiments, the alloy further comprises about 0–3% tin and about 0–2.5% germanium” (Wikipedia).