I am completely new to Unity 3D. I own the free version. For my first project, I am trying to make a MineCraft like clone. I followed tutorials, but now i'm trying to change something so it works how I want it. First off, how can I place a cube with a texture on it? Here's a chunk of code where I need to be able to do this:

function Build() { 
    if (HitBlock()) { 
        var cube = GameObject.CreatePrimitive(PrimitiveType.Cube); 
        cube.transform.position = hit.transform.position + hit.normal; 
    } 
}

This spawns a default cube with no texture whatsoever. How do I get a texture?

Here is my entire code ( I followed tutorials, so I shouldn't be saying mine):

var blockLayer : LayerMask = 1; 
var range : float = Mathf.Infinity; 
var hit : RaycastHit;

function Update () { 
    if (Input.GetMouseButtonDown(1)) Build(); 
    if (Input.GetMouseButtonDown(0)) Erase(); 
}

function Build() { 
    if (HitBlock()) { 
        var cube = GameObject.CreatePrimitive(PrimitiveType.Cube); 
        renderer.material.mainTexture = Resources.Load("Dirt.png");
        cube.transform.position = hit.transform.position + hit.normal; 
    } 
}

function Erase() { 
    if (HitBlock()) 
    Destroy(hit.transform.gameObject); 
}

function HitBlock() : boolean { 
    return Physics.Raycast(transform.position, transform.forward, hit, range, blockLayer); 
}