A tension set ring can make a statement when worn for special occasions or it can set you apart from the crowd if it is an everyday engagement or wedding ring. However, tension set rings emit immense pressure on your stone and require either a lot of metal or a very strong metal for the actual ring. Tungsten can be an excellent choice for a tension set ring, but only if you know what you are looking for.
Determine the Nickel Content of the Tungsten
Tungsten jewelry is not made from pure tungsten, but a mixture of tungsten and carbon with either cobalt or nickel as a binding agent. Your jeweler should be able to tell you what was used as a binding agent and either the percentage of the binding agent or the grade of the metal.
You should avoid tungsten rings with cobalt, as the cobalt can leach out of the ring and cause irritation to your skin. Inversely, the oils from your skin can permanently stain cobalt tungsten rings.
The nickel content of your ring may be between 3-30%. While most people assume that a lower binder content is more desirable, it actually depends on who is wearing the ring. If the ring will be subjected to repetitive force, such as routine work by a mechanic, you may want to look for something with a higher nickel content, as it will make the ring less brittle and more malleable. Alternatively, if you have a strong nickel allergy, you should look for something with less nickel. Low amounts of nickel in tungsten should not cause an allergic reaction because it does not leach out of the ring.
Select an Inlay, Not a Plating
Tungsten carbide is only available in a standard grey color. If you would like a ring that is brighter, black, gold, or two-toned, then you will have to get an inlay or a plating put on the ring. Unfortunately, plating does not withstand the pressures of daily wear the same way tungsten does. Eventually, your plating will scratch, wear off, or need polishing. To avoid this, you may select an inlay, which is slightly protected by its position in the ring and should last longer.
Select a Gemstone with a High Moh Rating
Gemstones are rated by their hardness using the Moh scale. The hardest gemstone, and the only one scoring a 10 on the scale, is the diamond. Other stones fall between 1-9. The tension used to hold a gem in a tension setting exerts a large force on the ring, and if you have a hard metal, such as tungsten, then the gem can scratch or shatter, leaving you with an empty ring. To avoid this, you want to choose a gem with a high Moh rating, usually a 9 or a 10. This generally limits you to sapphires, rubies, and diamonds.
Softer gems usually require a traditional setting or a softer metal, such as gold, for a tension setting. However, depending on the clarity of the gem, you may possibly go down to 8.5 or even 8 on the Moh scale without problems.
Selecting a Gemstone with a High Clarity Rating
The durability of a stone is determined by its hardness and its clarity. For instance, a diamond with visible inclusions may withstand less pressure than a ruby without any visible inclusions because the diamond will fracture along the lines of an inclusion when it is under the extreme pressure of a tension setting. Generally, when using the GIA clarity chart, you will want a stone that is considered VS2 or higher.
A tungsten carbide ring with a moderate nickel content and a hard, durable gem can last your entire life, with no problems. This makes tungsten wedding bands a great option when you want a tension set ring.