Mining items are fixed they are not changable...
Each ring gives out fixed items from the rocks....
Once you learn what ring type does what you look up rings not the item type...
Ring type is not a feature of inara...
This is handled by a different site...
Reserves and ring type are handled better by
edtools.ddns.net
Osmium is a metal and is listed as such in game so a metal is only found better in Metal rocks... metal rich and metallic rings...