so there are 7 levels of the lightning jewel, and 3 required to advance each lvl. I remember seeing a post that to make a noble jewel, it would take around 2187 or something like that to make a noble jewel (lightning jewel in this case)

So here's what i think

7 levels || 3 of the same kind to advance in lvl and stats

wouldnt it be like 3×7 = 21 jewels to form a noble one?

im confused....correct me if i am wrong.