How about a personalized stamp with their name or initials on it? You could also consider getting them a special stamp album with sheets to display their collection. If they don't already have one, a high-quality magnifying glass or loupe would also make a useful and thoughtful gift for a stamp collector. Finally, a coffee table book on stamp collecting or the history of postage stamps could be a great way for them to indulge their interest through reading and visual inspiration.
Or you can get her/him a star map with the date when she/he was born.
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.