multiple collisions to Destroy (gameObject);

i want to make it so depending on the blocktype, it takes multiple collisions to destroy without making a new script. heres what ive got on the block code.

using UnityEngine;
using System.Collections;

public class Block : MonoBehaviour {
	public BlockType blockType = BlockType.Wood;
	
	// Use this for initialization
	void Start () {
		MeshRenderer mr = GetComponent<MeshRenderer>();
		
		mr.material = Resources.Load ( "Materials/block" + blockType.ToString() +  " mat" ) as Material;
		
	}

	void OnCollisionEnter( Collision col ) {
		Score.score += (int)blockType;
		Destroy( gameObject );
	}
		
}

public enum BlockType {
	Wood = 10,
	Stone = 25,
	Brick = 50
}

Instead of calling Destroy immediately after incrementing your score, you have to decide if you want to destroy it first. To do that you should know how many hits it takes to destroy each block type. Then, each hit should increment a counter. Once that number is reached then you destroy it.

int hitsNeeded = 5;
int hitsTaken;

void OnCollisionEnter()
{
    Score.score += (int)blockType;
    if (++hitsTaken >= hitsNeeded)
        Destroy(gameObject);
}