Zircon is relatively common and has good hardness (7.5 on the Mohs scale), so its both widely available and well-suited for use in jewelry. It has a brittle stone, So it looks good.
The bracelets were worn as jewelry throughout the '40s. The popularity of ID bracelets spread to the civilian world in the 1970s as Americans began wearing them engraved with the name of soldiers reported either as missing in action or as being a prisoner of war during the Korean War or Vietnam War.
Cartier chains, also commonly known as link chains, are the most popular jewelry chain style for simple necklaces featuring a charm or pendant. This type of chain is made up of round or oval links of the same size.
The strong links that made the chain unbreakable are the very reason chains are often used to symbolize eternal love. The circle is eternal. It has no beginning and no end. This infinity linked to other circles in the chain makes its meaning all the more profound.