You are right it is an exponential and not linear. That is why I included a rank order. In terms of statistics, there is a major assumption about normality and homoscedasticity of the data. It is not clear to me that these assumptions are met. If not, non-parametric statistical test will be necessary.
I had a small sample size, but this correlation was not 100%. For example, wizards had the highest paragon ~3700 but were much weaker than monks and necromancers relative to their legendary gem levels @ 3400 paragon.
See: