Bohemian garnet brooch?

I'm not sure what to think of this brooch. The center stone is a lighter bright red and appears to be glass. The smaller stones surrounding could be garnet. All stones are set with prongs. The smaller 'garnet' stones appear to be hand cut possibly because they are not all uniform in their surface cuts and appear to differ slightly. The clasp is a trombone safety and has 'czecho slovakia' stamped on it in such tiny letters it's impossible to photograph. It measures 2" l by 1/2"h. I think it may be gold filled or gold over some other kind of metal. Has anyone seen anything like this? Is this a 1930's ish bohemian garnet that might have had a repair done with the center stone? or could the center stone have lost its foil backing changing its color?

 

It was quite common for Jablonec garnets to be mixed with Jablonec glass. This is between the wars.