Dichroic glass... proving to be a problem!

As you know I recently bought my glass fusing kit and microwave kiln... well it turns out that Alan is loving it just as much as me... which I think is a good thing as I don't have to explain myself when I spend up big on more glass and frit!!

Anyway Alan made a piece last week using a grape transparent glass and a black based dichroic glass as shown below.

Not sure what happened but the dichroic glass basically fused down into a big black blog with a shiny metallic area.

Sooooo if anyone has any ideas as to what we did wrong or has any suggestions we'd appreciate them!