You’ll need some fel iron to get through those skill levels. The green gems are common in fel iron, and you'll get them again in adamantite ore. I also find that mote of earth and fire seems to drop in more abundance from fel iron veins, though they can come from all those ores. You’ll need those motes, so save them up. Once you’re at the level for mercurial dust, then you can focus on adamantite. If that requires you to get to level 50, then you’ll need to do that too.