Another question about combo coticules!

[shotwell1234]

I picked up both of these at an auction and wanted to get some opinions on them. The stone on the right is a natural combination. The garnet matrix is pretty obviously visible. The left stone appears to be a glued combination (though I didn't show the sides). When lapped, the bottom seems to be a purplish color, as all other Belgian stones I have worked with have been. This leads me to believe that the top must be coticule, but, even under 10x magnification, I can't find the garnet matrix in it. They are both about the same size and weight, and both velvety smooth. Let me know if you guys can tell anything from the pictures, or if you have any other questions about them.