If you know a couple who have been married for 80 years, please congratulate them. They have had approximately the same number of anniversaries as the average person will have birthdays.
Traditional 80th-anniversary gifts include oak and rubies. These could be incorporated into your theme. Frankly, if your giftee has made it to their 80th anniversary, they likely don’t need or want any material gifts. Instead, consider gifts that honour them or can be dedicated to them.
80 is the atomic number for mercury (aka: quicksilver). The most common and well-known use for mercury is in thermometers. So obviously thermometers (outdoor, pediatric, meat, etc) are perfect gifts but also consider gifts that are associated with specific temperatures (eg: iced tea, hot chocolate, a fan for hot days).
Check out our general anniversary theme for more ideas around gifts, wrapping and presentation.