As of now both website say its caped at 51
Goldsmithing (51)
Yield: Amethyst x 1
HQ 1: Ametrine x 1
HQ 2: Fluorite x 1
HQ 3: Thunder Gem x 1
Wind Crystal
1 x Thunder Geode
http://ffxiclopedia.wikia.com/wiki/Amethyst
https://www.bg-wiki.com/bg/Amethyst
That's wrong I'm going past that at 53 an going...maybe i'm looking in the wrong place?