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Quality Assurance Benchmarks highlight workmanship of semi-finished and finished platinum jewelry. These examples illustrate methods for evaluating the quality and durability of platinum prongs and settings.

Side views of two platinum solitaires

The center stone is the appropriate size for the setting, neither too small nor too large

Prongs are stabilized by upper and lower gallery wires that limit their movement and enhance stone security

Prongs are angled at 70 degrees, reducing the amount of metal visible from the top

Prongs feature stable proportions and ample dimensions, and are made using a platinum alloy noted for hardness

Prongs are proportionately larger compared to nickel-based white gold prongs

Prongs are long enough to meet proper standards in accordance with stone-setting benchmarks

Side view of platinum solitaire with a split shank, with diamonds set in the shank

The center stone is the appropriate size for the setting, neither too small nor too large

Prongs are angled at 90 degrees

The prongs are tapered; they are wider at the bottom and smaller at the top. This design provides support and minimizes prong movement.

Wire motif provides additional support for the prongs

Prongs are proportionately larger compared to nickel-based white gold prongs

Prongs are long enough to meet proper standards in accordance with stone-setting benchmarks

Potential Problems and Engineering Features

In this example, a sales associate has sold a loose diamond and a platinum ring setting

Perspective view of a platinum solitaire with diamonds set in the shank. This same ring is also shown in a side view, with the loose diamond positioned above the mounting.

This setting is designed for a 0.50 carat center diamond

The setting was the last one in stock and was originally made for a much smaller diamond. However, the sales associate promised the ring would be ready later that day, and persuaded the in-store bench jeweler to set the larger diamond in the small setting.

Close-up side view of the platinum solitaire, with the loose stone positioned above the mounting.

To accommodate the quick turnaround and larger diamond, the jeweler was forced to alter the setting by pushing the prongs outward

A gallery provides enhanced stability. This setting has no gallery wire, allowing potential prong movement and increasing the risk of stone loss.

Close-up side view of the platinum solitaire, with the loose stone set into the too-small setting.

This diamond is set in a too-small setting. Because the prongs were spread, very little metal was left for setting.

Spreading the prongs too far weakened their structure. They are now vulnerable to being bent farther outward, resulting in stone loss.

Prong contact over the crown was minimized. This setting is vulnerable to stone loss.

This platinum setting is made using a process called die-striking. The prongs are cut away from sheet-stock by a die, assembled, and then oven-soldered. Once they are made, they are torch-soldered into the setting.

Perspective view of die-struck platinum solitaire

Platinum die-struck parts are often made from dies that were originally designed and engineered for nickel-based white gold products. Platinum prongs made from dies engineered for white gold are too thin. They can move during manufacture and normal wear.

Platinum alloys are more malleable and are not as hard as nickel-based white gold alloys with similar amounts of base metal. One of platinum’s many positive attributes is its malleability. When formed or bent, it does not spring back like white gold.

When die-struck settings are soldered onto a ring, the process typically results in the annealing of the prong metal, making them more malleable and easier to move

Real Life Consequences: This is a real story, but some details have been changed. A retailer designed and created a custom platinum setting for a 22.50 carat round brilliant diamond. The ring was hand fabricated using 90% platinum/10% iridium, which is among the softest and most malleable of all platinum alloys.

Close-up view of a platinum solitaire setting of the 22.50 carat stone, with the prongs set with baguettes.

There is very little prong contact

The prongs were set with baguettes, which required them to be hollowed. Most of the structural support had to be removed, compromising stone security.

A minimal amount of metal was used in the setting and ring mounting

The prong angle is steep, making the prongs more vulnerable to bending outward during normal wear

Close-up view of a platinum solitaire setting of a 22.50 carat stone, with the prongs set with baguettes.

During the first hours of normal wear, the ring was struck from above and the 22.50 carat center diamond was LOST! It did not take a great deal of impact or prong movement to cause the setting to open and the diamond to fall out.

The impact forced the diamond downward, which in turn pushed the prongs outward, releasing the diamond. Inadequate prong contact contributed to the loss of the stone.

The low-level gallery provided little support

Platinum prongs have no memory, meaning they will not spring back when bent. No metal memory is highly desirable for prongs with proper dimensions, as the lack of spring-back increases stone security.

Steep angles made the prongs vulnerable to bending outward. Additionally, all prongs were hollowed to accommodate the baguettes that were set in them, further weakening the structure.

Real Life Consequences: The original ring’s fragile custom mounting is shown next to one made using the specifications for a secure setting. With a 22.5 carat diamond, a setting should minimize potential for loss.

Two illustrations side-by-side: the first is the original ring’s mounting, and the second a mounting illustrating the parameters for a secure setting, including proper prong contact, prong angle, and gallery height.

This illustration depicts the original ring’s setting. The prong contact is only 12%, and the prong angle is only 55 degrees. The upper gallery location provides minimal structural support for the prongs.

GIA
Two illustrations side-by-side: the first is the original ring’s mounting, and the second a mounting illustrating the parameters for a secure setting, including proper prong contact, prong angle, and gallery height.

This illustration depicts parameters for a secure setting. The prong contact is 25%, and the prong angle is 62 degrees. The upper gallery provides sufficient structural support for the prongs.

GIA

Featured Quality Assurance Benchmarks

Set a Round in Platinum Prongs

Setting a round center stone in a ring with platinum prongs

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Set a Princess-cut in V-Prongs

Setting a Princess-cut Center Stone in a Platinum Mounting with V-Prongs

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Sizing Up: Platinum Alloy

Sizing Up a Platinum Alloy Ring with Diamonds Using a Torch

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Refinish Worn Platinum Jewelry

Techniques for refinishing worn platinum jewelry

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