Boreal Quartz gemstone 25.75 ct

Boreal quartz is a type of quartz of natural origin but probably treated by irradiation and heat treatment.

The exact process is not known.

I bought the treted rough material from Pakistan. In any case, stones are cut with a pleasant opalescent effect.

Normally the irradiation treatment on clear quartz produces black quartz. Then if these black stones are heated, the quartz becomes transparent again. In some rare deposits the process is not completely reversible. This is the origin of Lemon Quartz and many other oddly colored quartzes. But the treatment of this specimen is not known yet.