Mafia 95. The Wardens' campaign against Urubaen.

I'm starting to generate information about Berbers, whom you don't necessarily have to trust, but they might lead you to something.

Onyx is one of the "Biblical stones." The Bible states that the breastplate of the High Priest, which he wore during worship, was adorned with twelve colored stones, including onyx.

In the "Bible" tab, under the very first picture, there is a caption "Gutenberg Bible," a copy of which, according to Wikipedia, is kept in Mainz. One of Mainz's twin cities is Dijon.
The downside of this Berber is that I couldn't go back from the Bible to the stones (maybe I just didn't look carefully enough), and in the "Breastplate" tab, there are also ruby, topaz, agate, and chrysolite (you can associate them with whoever you want; for mapmakers, it's a goldmine, although the mention of Biblical stones is only in the article about chrysolite).

My eyes are starting to hurt after only an hour and a half in Wikipedia :)