It is customary in to give presents on anniversaries.
This has been a custom since the ancient times.
In the West, this custom has a tradition of what kind of gifts to give. Some of the years might vary according to sources but here is a guideline for gemstones.
12th year Agate
13th year Moonstone
15th year Crystal
16th year Topaz
17th year Amethyst
18th year Garnet
23rd year Sapphire
30th year Pearls
40th year Ruby
45th year Alexandrite
50th year Gold
55th year Emerald
75th year Diamond
If you married around the age of 20 on your 40th anniversary you'll be around 60; the year of ruby.
This corresponds with a custom in Japan. In the celebration of reaching the 60th year birthday, it is customary to give red thing.
It is believed that if you wear red it will revitalize your energy and you can continue life with vigor.