One possibility is to randomize the selection of blocks with a given oredict name. This would be useful for example, oreCertusQuartz is present on both certus quartz ore and charged certus quartz ore, however the mineralis ritual consistently produces charged certus quartz ore.

That's because of how it registers in oredict. Address it with the mod adding the ores to the entry for ordering.

Or remove the oredict entry, and set the specific ores you want to use instead. Anything else defeats the purpose of the oredict.

you can set specific ores in config? okay then. that works.

Yes, it autopopulates from the registry, but you could specify a specific mod's ore type instead, or remove entries, or add non-oredicted ores if you wanted.

@Doomgull how do you specify specific ore type? The config file mineralis_ritual.cfg doesn't seem to accept block ID's i.e. (appliedenergistics2:ore_quartz) in place of an oredict name.

Use crafttweaker to define a new oredict and add just that one ore to it.