Connect walls of two same gameobjects

I have gameobject which is regular tetrahedron. I want to instantiate next one, but connected with wall to the first. Finally, it should look like this:

I calculated that angle between base and wall of regular tetrahedron is deegres(acos(1/3)) = ~70.528779°. My problem is I can't find way to rotate and snap new object to the 1st. This is part of code I wrote:

 //hitBlock is the 1st tetrahedron
 hitBlock = Physics.Raycast(transform.position, transform.forward, hit, hitRange, blockLayer);
         if(hitBlock){
             var block : Rigidbody = Instantiate(blocks[i], hit.normal + hit.transform.position, Quaternion.LookRotation(hit.normal, hit.transform.up) * Quaternion.Euler(-2*(90 - (Mathf.Rad2Deg*Mathf.Acos(1/3))), 0, 0)) as Rigidbody;
              
                 Debug.Log("Placed new object "+hit.collider.name);
         }

Unfortunately it does not work properly. I was searching for solution on the Internet and in Unity API, with no results.