Setting a Round Centre Stone in a Ring with Platinum Prongs

Quality Assurance Benchmarks highlight workmanship for semi-finished or finished jewellery. Learn how to evaluate the quality of the setting of a ring with platinum prongs.

Close-up side view of platinum, four-prong solitaire with a round centre stone

The prong is in contact for 30-50% of the distance from the girdle to the table of the stone

Prong height is 60% to 80% of table height

Close-up view of a four-prong, platinum solitaire with a round centre stone

40% of the metal is removed from the prongs’ thickness at bearings

The top of each prong is in full contact with the stone’s crown

Gallery wire strengthens the overall prong assembly

Prongs are angled outward from the base to the top of the setting

Setting and prongs are free of debris and exhibit a bright lustre

Diamond is level, with no gaps between the stone and the bearing above or below the girdle

Close-up perspective view of a four prong, platinum solitaire with a round centre stone

No tool marks inside the setting or on the prongs

Prongs are evenly rounded and consistent in size and shape

Potential Problems and Engineering Features

The following problems can occur due to errors in workmanship:

Bearing has been overcut, so the remaining prong width is too thin

Bearing does not conform to crown and pavilion angles, and is larger than the stone’s diameter

Under normal wear, significant impact to the top of the stone will cause the prong to move outward and the stone to loosen or become dislodged

Close-up view of a four-prong, platinum solitaire featuring no bearing in the prong for the stone but with a small amount of metal formed over the top of it.

The prong is in contact for only 10% of the distance from the girdle to the table of the stone

No bearing or seat, so the stone is not supported

Setting a Round Stone in a Solitaire Ring with Platinum Prongs

Setting a Round Stone in a Solitaire Ring with Platinum Prongs

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