i mined around 30 ores i had saved up with fortune 5, and between 5 to 6 dropped no gems at all.

I think this may be fixed; it would be an issue with MysticalLib if it was one at all -- the code is practically identical to how vanilla handles fortune, so I'm not really sure why it would happen like that.

(I'm not closing this as I don't know if it's fixed or not. I'll test it in dev later today.)

I tested this with Fortune 5 and 64 ores and got gems from all of them, so I think the recent change to Mystical Lib will fix this in the next release.