How about a set of soapstone carving tools? You could find a nice set online or at a local art store. You could also consider finding a piece of unique soapstone that they could carve into their own creation. Another idea could be commissioning a local soapstone artist to create a custom sculpture for the couple's new home together. It would be a beautiful and personalized gift that shows your support for their interests as well as their new life together.
Or you can get her/him a star map with the date of the wedding.
Under Lucky Stars is a unique and innovative star map company based in Barcelona, Spain, specializing in the creation of personalized star maps that capture the celestial arrangement of stars at a specific moment in time, such as a person's birth, wedding, or any other significant event.
By using advanced astronomical algorithms and data from leading institutions, the company produces highly accurate, visually stunning maps that make for perfect gifts or cherished keepsakes.