When I add a gameObject from one list to another, it makes a new one instead of referring to the same one?

I have a two lists. Variable 'openList' is a list of my own type 'AINode,' and blockList is a list of GameObjects. Whenever I try to add a blockList element, It copies the gameObject in blockList. I wanted to simply refer to the same GameObject instead of making a copy. This is the code I'm using:

             openList.Add( new AINode(new Vector3(curPos.x,0,curPos.z), blockList[(int)(curPos.x+1)][(int)(curPos.z)][1]) );

//Any help is greatly appreciated :D