The precious stone traditionally given on the 40th anniversary is the ruby. Known for its vibrant red color, a ruby signifies love, passion, and commitment, making it a fitting choice for honoring four decades of marriage. Rubies are part of the corundum mineral family and are valued for their hardness, second only to diamonds on the Mohs scale. Their rich color comes from the presence of chromium, and high-quality rubies can be quite rare and expensive. The tradition of gifting rubies complements the milestone anniversary, symbolizing enduring love and a deep emotional connection between partners.