Max Efficiency on pickaxe possible

[Asmecamete]

So, i've finished almost every quest on skyblock and began working on upgrading tools and i'm upgrading diamond pickaxe, right now it's on efficiency 5 and whats best possible level for efficiency? is there some kind of limit on efficiency or it just becomes faster and faster on every enchantment?

 

[Xavi | Goofy]

I recommend enchanting it until level 8 as this will instantly mine all ores. (With haste II, or eff9 w/o). You can put 20 levels on efficiency but this wouldn’t add much. The best possible pickaxe is eff8 and fortune 12 in my opinion.