The 45th anniversary is the sapphire anniversary. Traditionally, sapphires are blue, but sapphires are actually found in a variety of colors and shades. According to Gem Select, natural sapphires are usually pale and light in color.
After the diamond, the sapphire is the second-hardest mineral on earth. The sapphire is a gem-quality variety of corundum, a mineral. Although corundum is not a rare mineral, the gem variety of this mineral is very rare. Most mined corundum is opaque in color and only suitable for industrial use. When a gem-quality corundum is deep red, it is classified as a ruby, rather than a red sapphire.