guiTexture color half alpha White?

So i have a guiTexture that needs to be half Transparent. Like half see through, but not all the way clear... Any ideas? This is what I have so far in JS...

 #pragma strict
 
 static var CanMove = false;
 static var ShowGUI = false;
 //var Click1Sound: GameObject;
 
 function Start () {
 
 CanMove = true;
 ShowGUI = true;
 
 }
 
 function Update () {
 
 if(ShowGUI == true ){
 
 
 guiTexture.enabled = true;
 
 
 }else{
 
 guiTexture.enabled = false;
 
 }
 
 
 if(CanMove == true){
 
 if(Input.touchCount > 0 ){
 
 for(var i : int = 0; i < Input.touchCount; i++){
 
 var touch : Touch = Input.GetTouch(i);
 
 if(touch.phase == TouchPhase.Began &&
 guiTexture.HitTest(touch.position)){
 
 
 
 CameraCUSTOM_Movement.MoveRight = true;
 
 }
 }
 }else{
 
 // this makes it all the way clear, but I want it to be half way
 
 guiTexture.color.a = 0;
 
 //////////////////////////////////////////////////////////////////
 
 
 CameraCUSTOM_Movement.MoveRight = false;
 
 }
 }
 }

Thanks- :)