In recent years I have been looking for a cost effective sterling silver
alternative in the face of rising gold and platinum prices, but I also
needed a metal hardness suitable for diamond setting. A variety of
new sterling silver alloys have been introduced to the jewelry industry
recently, but apart from anti-tarnish improvement, the real mechanical
strength problem has remained. Lack of hardness often results in
difficulty with finishing, design, shape retention, and stone security.
I had asked many of my metallurgist friends and contacts in the
industry, but the answer was always the same; with only 7.5% of nonsilver
components in sterling, hardness similar to 14kt gold would
appear to be impossible.

That is until Darrell Warren, Vice President of Merchandising at Stuller,
revealed that no one had told this to John Butler, a 22-year veteran of
the company and a member of Stuller’s Research and Development
Department. What had appeared to be impossible to most in the
industry has become a reality at Stuller. John Butler had invented what
is now called Continuum.

Testing Continuum

After learning of this new alloy, I was given the opportunity to be one
of the first outside the company to test the new alloy. To do this, I
designed a range of pieces with high detail in light profiles that would
normally be reserved for platinum or gold castings.

After learning of this new alloy, I was given the opportunity to be one
of the first outside the company to test the new alloy. To do this, I
designed a range of pieces with high detail in light profiles that would
normally be reserved for platinum or gold castings. the re-casting ability
of Continuum is exceptional. Up to four re-casts can be achieved without
the need to add any fresh grain.

Casting Properties

  • Rough castings resemble platinum or gold castings
  • No oxidation layer that requires mechanical cut down or chemical stripping
  • Design detail is preserved due to the lack of surface reduction

Annealing and Age Hardening

  • Rough castings or "as-cast" has a hardness range os approximately 100 to 119 HV (Hardness Vickers), comparable to .950 platinum ruthenium castings
  • Maximum hardness is achieved when the castings are annealed and quenched in water followed by a short age hardening protocol
  • 158 HV can be achieved after hardening, making it comparable to the "as-cast" hardness of 14kt white gold
  • Metal retains shine throughout the age-hardening process without signs of heat staining
  • Remains ductile even after hardening, showing no signs of brittleness

Fashionable Endurance

Kristi Broussard, a Stuller master stone setter, has been proudly wearing a Continuum band with prong set stones for the past 18 months. The ring shows no signs of tarnish, prong or shank wear, and stays in round. 


About the Author: Vic Joyner has been a bench jeweler for over 30 years and a Stuller customer for over 25. His background is in traditional metal smithing and industrial design. He invented the HD Pattern System, found online at www.stuller.com. A part from his design and bench work, Vic consults with jewelry manufacturers on the integration of CAD design to production. Look for him on benchjeweler.com as boat jeweler