Bharatheeya Temple or Kshetram is an energizing center. A kshtram normally follows mainly 2 types of aradhana krama or methods of worship.
1) Vaideegam. Homam or havan aradhana in which we offer various things to Agni
2) Pauranika aradhana kramam. This is where vigrahas are established inside the sreekovil or the main block of the temple and worshiped upon
Vigraham can be of 8 types
1) Hard stone
2) Red stone or clay stone
3) Marble
4) Wooden (Daaru shilpam)
5) Metallic (Panchaloham or any other metal)
6) Drawing or Painting
7) A lamp
8) Manoroopam (i.e. an image in your mind)
Kshetram or temple is like a yaga shala. It has a place called Uthara vedi, which will be either a square or circular. This is where the vigraham will be established.
Courtesy
Dr N Gopalakrishnan (Indian Institute of Scientific Heritage)
http://www.youtube.com/watch?v=7pVWFnKymBs