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.