I'm a noob. How much crystal need

How much crystal will you guys recommend before trying to upgrade 1 item?

I tend to save 3 or 4 each of Obsidians and Amethysts before using them per item. Both crystal these crystal tiers have a relatively smaller affix list compared to Ruby, which I tend to get 6 or more before using. Of course, all of these depend on your (real life) luck.

It’s a bit easier now to gather crystals, since you can convert legendary grade items to rare crystals (I think starting from Peridot and up). All you need is a lot of gold.

Also, are you planning to modify that Eternal Blessing of Faun? Eternal items cannot be modified by crystals, except by Calcite (change element), Beryl (change nature), Larimar (add normal affix) and Topaz (add epic affix), that last two of which you cannot do unless your Eternal item is glitched by missing affix/es. I dunno if Garnet (remove socketed Mythstone) can work on Eternals though.

I think larimar and topaz can only be added to a eternal mythical sword/helm because it has 4 empty sockets that you can make a mythic from it.

Affixes it has will be
Mythical Set affix
Mythology
Chosen mythic
missing affix
missing affix
missing affix (that you can use topaz and larimar)

@VicBot:
I usually use crystal legends as a base if I could use it as a build so I don’t use a lot of obsidian.
I plan the build so that I won’t waste crystals. I list the affix that I need.
I always raise the quality of the item so you need a lot of emerald.
if the quality is at 0 you need 25 emerald.
To max out item lvl you need peridot but usually it’s low number of uses

This helped me a lot on crafting.

Ty and Ik you can’t enchant eternal I was just showing it lol

Ty

Garnet can use on eternal to remove socketed MS.