Smoked Ethiopian black opals

Smoked/Heated Welo (Ethiopian) Black Opals

Hello all.

How does one tell if a Welo Black Opal has been heated/smoked to
enhance the color? Any and all replies are welcome. Thanks in
advance and I hope everyone has a great holiday season.

Paul B.

Magnification shows black deposits in the surface-reaching pores,
cracks, abrasions. The stone looks dirty.

Hi, I’ve handled lots of Welo opal and have yet to see one that was
naturally black. In the last couple of years I’ve seen a few that
were obviously smoked or sugared. Sugaring involves soaking the
stone in a sugar solution and then putting it into a strong acid
that blackens the sugar. If it’s Welo opal and it’s black then I
would assume it has been treated in some way. Almost all Welo opal
is clear to translucent, some is white, lots are orange but never
black to my knowledge, though there could be exceptions. Best
wishes, Douglas