I love Pinterest for finding similarly-minded Roman and Byzantine jewellery fans and for sharing all sorts of awesome. Including this pair of earrings that's housed at the V&A. (Provenance can be found here.)
Even though these are a little more complicated than I can do right now, I can at least come close with what I do have.
Let's look at the extant piece: emeralds, sapphires, and pearls. Emeralds and sapphires can be on the expensive end, but freshwater pearls less so. Amethyst is another material that was used extensively by Romans, as it invoked the Imperial use of purple. Instead of pure gold, using hammered brass wire can at least come close.
It is still not as period as I would like, however this evokes the original closely.
See what you've got in your craft stash and see what you can figure out!