[Tanoa] Going down the diamond route

[DTYlan]

Using the key on the map, I find that there is no actual diamond processor. The key states that a square is a legal processor and a circle is a buyer. Which means Tanoa jewellery is a processor but there is no option to get diamond training there. 

So which is the actual diamond processor?

 

[Hoax]

the ring maker

 

[Oliver V2]

Ring maker.

 

[DTYlan]

Ring maker.

the ring maker

Thanks Bois