Zircon is mined down tunnels that go down to a gravelly layer where the rounded zircon pebbles are found.  A pump is needed to pump out ground that constantly seeps in.  I believe this stone is unheated because it has not changed color while sitting on the window sill in sunlight for a few months.   Normally heated stones change color after a while in UV sunlight.

Beautiful cut with great reflection.  No shallow window or too deep giving a heavy bottom which is hard to set.    

Video and photos taken with imax 12 pro on HD 30 setting original setting.   No added color.  Stone will look as it does in the photos and video when you see it in person.  VVS clarity.   Very nicely cut for full reflectivity and easy setting for a ring stone.