Amethysts and Emeralds are the gems I have the most trouble acquiring from mining. I’m looking to buy enough refined amethysts to mass craft some helixes. Is anybody selling them, and how much would you want for 231?
There’s some for sale in the Crypt Hub in the Ultima Guild HQ on Finata - Just look for a large black tower with Crypt Hub on the side 
All the parts you need to make them are in there iirc. There’s some stands in the centre with DIY Coils on a sign