Biased: From Australia. Get an opal? or more general advice "consider other stones to diamonds".

Gold is pretty; White gold is too (and cheaper)

Bonus: Magnetic wedding band. neat, unusual, practical. (Disclaimer: I just purchased for testing out magnetic-sense https://www.supermagnetman.net )

My sister and her partner made their own wedding rings at a custom-wedding-ring-jewellery place, but I have no idea of the details.