Anniversary gemstones by year.

How the gemstone list works

The American Gem Society standardised the gemstone list in 1957 by drawing on existing jeweler conventions plus older traditions: black onyx for year seven traces to ancient Roman marriage longevity; lapis lazuli for year nine carries Mesopotamian royal weight; jade for year twelve borrows from Chinese marriage symbolism. The list filled in the gaps between the major-milestone gem years already established in the traditional canon (ruby at forty, sapphire at forty-five, gold at fifty, emerald at fifty-five, diamond at sixty).

Some later additions are recent. Tanzanite for year twenty-four was added in 2002 by the American Gem Trade Association after tanzanite became widely available (it was discovered in 1967). Alexandrite for year fifty-five is the most chromatically dramatic stone in the canon.