It seems obvious enough from the CoreResources.xml file.
<Shared>
Shared resources get hauled in caravans and given bonuses when roads are connected (food).
Un-shared resources are held within their city, not giving bonuses to friendly cities (population, prestige, etc)
Code: xml
- <ResourceType InternalName="GoldType01">
- <DisplayName>Gildar</DisplayName>
- <Type>Gold</Type>
- <IconColor>0,0,0</IconColor>
- <Icon>Gfx//Icons//Res_Icon_Gold.png</Icon>
- <ClothIcon>gfx\\TacticalIcons\\MetalOre_1.png</ClothIcon>
- <ModelColor>0,0,0</ModelColor>
- <Worth>1</Worth>
- <Global>1</Global>
- <Rarity>0.0</Rarity>
- <Shared>0</Shared>
- <TradedByCaravans>1</TradedByCaravans>
- <ShownInGlobalDisplay>1</ShownInGlobalDisplay>
- <Medallions InternalName="Gold_Res_Medallions">
- <All>Res_Ores_Plains.png</All>
- </Medallions>
- </ResourceType>
- <!-- ************* -->
- <!-- ** Rations ** -->
- <!-- ************* -->
- <ResourceType InternalName="RationsType01">
- <DisplayName>Food</DisplayName>
- <Type>Rations</Type>
- <IconColor>0,0,0</IconColor>
- <Icon>Gfx//Icons//Res_Icon_Food.png</Icon>
- <ClothIcon>gfx\\TacticalIcons\\MetalOre_1.png</ClothIcon>
- <ModelColor>0,0,0</ModelColor>
- <Worth>5</Worth>
- <Global>1</Global>
- <Rarity>0.0</Rarity>
- <Stored>0</Stored>
- <TradedByCaravans>0</TradedByCaravans>
- <ShownInGlobalDisplay>1</ShownInGlobalDisplay>
- <Medallions InternalName="Ration_Res_Medallions">
- <All>Res_Ores_Plains.png</All>
- </Medallions>
- </ResourceType>
Rations AKA Food is shared by Caravans, and no other resource is. But fiddling with this does nothing to allow Gold to be traded.
Which leads me to believe it's probably hardcoded or something.