Thanks for the answers SLAG and Thomas,
My clever nuclear chemist wife immediately pointed out the oxidation problem, but wonders why the Widmanstetten patterns do not oxidize naturally. Anyway, that is off-topic.
I do not have a pallasite specimen, I was thinking of purchasing one, sawing out the olivine and using the metallic matrix for the ring. Now I see that is not the way to go as it appears most meteorite rings are not cast.
I think I will go the easy route and just purchase the olivines from here
http://www.kdmeteorites.com/2mmCalibratedMeteoritePeridot.html
And getting these people to make the ring.
https://jewelrybyjohan.com/collections/meteorite-rings
Thanks again for the help,
Geologist Paul out