Unity 2D - Issues Making an Item Collectable

In my game, I have Diamond objects tagged as “Diamond.” I have the following C# script attached to my Player object (tagged Player). However in game, the Player just pushes the Diamonds around when it touches them. I have a Rigidbody2D and a Box Collider 2D on the Diamonds. What can I do to make the Diamonds disappear? Thanks.

using UnityEngine;
using System.Collections;

public class Diamonds : MonoBehaviour 
{
    void OnTriggerEnter2D(Collider2D collider)
    {
	    if (collider.gameObject.tag == "Diamond") 
	    {
		    Destroy (collider.gameObject);
	    }
    }
}

Check these answers: