i loaded my old save and no longer have Amethyst is there a way to find it again
The process for getting an amethyst is:
1 - Research Rockbiters (I might have to change this to be more broad as the greenthorn recipe also needs an amethyst but that's neither here nor there)
2 - Ask Jessica about acquiring an amethyst
3 - Wait 3 in-game days
4 - Jessica will tell you after those days that she has one and you can then buy it
If your old save doesn't have one, you have got the Rockbiter research and you can't ask Jessica about it, it's possible you saved during the waiting period. It's either that or some flags have been broken somehow, which can be fixed with some console commands if needed.