Wednesday 30 June 2010 Blue diamonds A square and a rectangular radiant cut diamond. The color of most blue diamonds is caused by the presence of boron: the higher the concentration of boron, the more intense the color. Share this post Share on Facebook Opens in a new window. Tweet on Twitter Opens in a new window. Pin on Pinterest Opens in a new window. Share on LinkedIn Opens in a new window. Share on WhatsApp Opens in a new window. Back to blog