The earliest know references are to Silver (25th Wedding Anniversary) and Gold (50th Wedding Anniversary). These appear to originate in Middle Europe (Germanic Region) and involved the spouse giving his wife a silver garland when they had been married for 25 years. Some European countries also celebrate Twelve and a half years of marriage using Copper as the Anniversary Symbol.
We have found references to materials associated with specific years which follow the traditional anniversary lists for the first 5 years of marriage and then every 5th year up to 25th and then 50th and 75th.
The earliest reference we have found other than the Silver or gold is to the 5th anniversary (Wood) which implies this became the material for that anniversary around 1875.
There are currently 2 Diamond Anniversaries, one at 60 and one at 75 years. The 75th anniversary is the original traditional diamond anniversary with the 60th being added when Queen Victoria (English Empire Monarch) celebrated her Diamond Jubilee on her 60th anniversary of accession to the throne in 1897 and this has since been adopted as an appropriate Wedding Anniversary also.
In 1937 the American National Retail Jeweler Association issued a more comprehensive list which associated a material for each Anniversary year up to the 15th Anniversary and then each fifth year after that up to the 60th Anniversary.
Additional lists are issued from time to time however the one quoted above is more or less the de-facto list for the Traditional names of Wedding Anniversaries.