The above piece of trinitite is rare. It has an unexplained blue color in the center of the piece. One theory I have heard from a very reliable source on trinitite, is that this, and other such colorful inclusions are examples of more complete melting that may have taken place when a small mineral grain or bit of “trash” at the site reduced the melting point of the mixture and caused a better grade of glass to form.
Blue piece: 3.2 gms.