This is another one of those "learning experience" projects. It did not turn out remotely like I wanted it to, but I think it might be a stepping stone to get there. Just probably not in the next 3 weeks.
The large jewel sort of stuffed into the front of Lucretia's dress is rather intriguing. It has pinky/red gems and blue ones with a drop pearl. It has foliage and figures and the center is a giant flower. All kinds of interesting stuff going on. Wikipedia's zoom is loads better than the images at the National Gallery and allows you to see the spiky topped flower stems and the faces of the cupids/putti.
While I would like to make a reproduction of the portrait jewel (in Sculpy since that's as close as I'm going to get to gold) I'm not so sure about my ability to sculpt it. I started on it and the proportions were not very good. I was having a tough time with the total 3 dimensionality of the putti. The entire piece also didn't seem particularly stable. And then my son tried to eat it and I gave up once I wrestled it away from him. I figured I'd start with something a little easier after that. I found this simple pendant dated 1540-1560 at the V and A (museum number M.242-1975) It is that simple because it is more concerned with the efficacy of the stones and their value as talismans, but I love the lines of it. I bulked it up a bit, both because of my sculpting ability as well as needing something more monumental.
Here it is before it hit the oven.
As I said, learning experience. I thought the acrylic would look fine since they are table cut. The color is a huge issue, however. Some colors look fine and others do not. While the blue and pink is actually pretty close to those in the original jewel, using a semiprecious stone of some kind might be a better option, especially to counterbalance the fact that I'm using a polymer clay. Another few attempts at sculpting is going to improve things over all, and I might get crazy and try the figures in the portrait. I think a bad looking attempt at the portrait necklace is going to make me feel better than a marginally better attempt at something that is already a compromise.
So, making my own sculpted medallions/pendants is going to go in to the pile where comb making is. I'll try again another time. Its something that I certainly want to figure out at some point.