How to mine a diamond in three steps.
Minimize inherent bias in recruiters or hiring managers.
Hire for skills. Move away from functions (and their titles) and embrace skills (hard-skills and soft-skills, combined) instead.
Provide a non-linear career perspective. Based on the hard-skills and soft-skills, combined with the talent’s willingness to learn, draw a roadmap with possible career choices within your company.
There is, however, one caveat to this approach. You can’t polish a gem if you’re not willing to dig up the diamond.