Due to some confusion about resource types 1.3.1 will introduce the resource type icon as a part of the resource button in the trade window.
Before the patch is released here is a description of the resource types.
The Atom = Technology Type. (Scrap, Nano Bots, Ship Engines)
The Tree = Organic Type. (Wood , Food, Oxygen)
Pink Diamond = Gems (Crystal, Siliumantite, Amandamite)
Gold Bar = Metal (Iron, Gold, Palatium )
Brown Box = Normal (Not seeking or selling any specific type)
Hope this is of some assistance.