There are plenty of resources that quote what material or name is associated with specific wedding anniversaries. Have you ever asked why this material is chosen? We did and effectively this web site is the result!
We are constantly researching the reasons why a material is associated with a Wedding Anniversary and have published what we have found out to date on the pages below;
The majority of these lists converge on the major anniversaries e.g. 25th is Silver and 50th is the Golden anniversary across the different lists. I suspect the reason for this is that these wedding anniversaries have created the tradition and an alternative material would not be accepted and hence not be used.