Here is the system map. Bodys closest to the star are most likely to have volcanic/geyser type activity, me thinks. This system is well stocked with Ruthenium.
These needle type structures are the most valuable, holding the rarest materials.
I have investigated several sites and they contain a lot of materials to collect although about 50% of that is the common ones.
Collecting materials from a geyser site. A good way to stock up on elements. In this case, in system Synuefe XR-H d11-22, planet 1. Some of the sites can be very scenic., like this one.