You may have seen them yourself - floating in the middle of a marble - an opal.
Well - you know a thing or two about opals - it being your birthstone and all - and you know that a real, live, mined-out-of-the-ground opal would never survive the heat of being worked in glass - so ask - and it turns out to be a Gilson Created Opal - embedded in borosilicate glass.
And there it ended - because the word is that the Gilson Opal (artificial opal) is a close enough COE to the boro that you can include it.
Which would indicate that would not work in soft glass.
Well - that would be correct.
When I heard a rumor that you COULD put opals into soft glass - I was all over it like dog hair on a velvet couch.
But, sadly, the answer is, no, it's not compatible.
This is the remain of a marble and a bead. They blowed up good.
I tried both the black opal and the white, in various sizes - even the utterly minuscule ones broke the glass. The shards of opal that fell back out of the glass retained their fire and brilliance (as you can see).
The original premise stands. Not compatible.