How about gifting him a shadow box display case so that he can show off his favorite arrowheads? You could also consider purchasing a book about the history and mythology surrounding arrowheads, or even plan a weekend getaway where you both can go arrowhead hunting together. If you want to go the extra mile, you could even get a custom-made arrowhead necklace or bracelet for him to wear.
Or you can get him a star map with an important date you share.
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.