Ghpstage
Deity
Not sure exactly what you mean, but it sounds like your misreading the city screen.So it it says I'm trading gems 1of 4, that means I had 3 extras? And in order for all cities to use them, they all have to be linked together through a trade network?
I have roads between all my cities, but everytime I look at my city map, it shows that my trade is only with two of them. How come they aren't all connected? It is the first two cities I built though, I think
In the pic below the cities named in the red box I marked are trade routes. These give

The area I marked with yellow is part of the city resource box, it shows all the resources this city has access too. If you want too see if your trade network is allowing your cities to use your resources, then this is what you should check
Spoiler :
