Tension ring

Second, tension settings are calibrated to the exact specifications of the stone that they hold, therefore they cannot be manufactured until the customer has selected a gem.

A tension ring is a robust assembly, generally exerting around 12,000 pounds per square inch of pressure.

This requires careful calculation, and inspection of the gem to ensure that every facet mates perfectly with the ring.

Tension rings are also manufactured using other metals, particularly those that are naturally strong, such as titanium or stainless steel.

These materials are usually used for "fashion" jewelry, and are set with small diamonds or semi-precious gems such as topaz or tourmaline.

Tension manufacturers partially agree with this statement, warning their customers that stones can be lost if the setting suffers a blunt force impact that damages the spring-loading, but they also point out that no stone has ever been lost as a result of a manufacturing defect.

Tension settings on the other hand do not need to be replaced, and unless the spring-loading is damaged, are unlikely to lose a gem stone.

[1] However, the general concept of tension settings has been around for over 40 years as it was developed in the late 1960s by a Niessing employee named Friedrich Becker.

The alloys in the 18 karat blend were non traditional jewelry metals, used to give the ring much greater strength than normal.

This has since been licensed to other companies, for example Hoover & Strong, who require a super hard platinum alloy for jewelry such as tension set rings.

Steven Kretchmer's advancements in the alloying of metals allowed the modern day tension ring to lose much of its weight without sacrificing strength.