These are separates from a altered detrital sample. Barite is obviously heavy and non-magnetic, so we are dealing with the final non-magnetic heavy fraction. Obviously the goal here is the zircon, not the barite.
Zircon is non-conducting, slightly radioactive and flourescent, with Specific Gravity of 4.85 gm/cc, with hardness of 7.5, which is greater than that of baryte, i.e., 3-3.5.
The specific gravity of baryte is also less than zircon, i.e., 4.48gm/cc with careful use of heavy media and other criteria such as it is not radioactive and not flourescent,
At the Arizona Laserchron Center we use a dentistry tool called the Wig-L-Bug to pulverize soft minerals (commonly barite) that make it through density and magnetic separation. This process is detailed on the ALC web site (laserchron.org) and in this PDF
One issue here is the removal of barite, but the retention of all zircon. For typical zircon, we are fine, but with high-damage zircon there is a concern with chemical approaches.