The super structure that will be visible to all visitors is made of specially selected sandstone.
The Ram Mandir at Ayodhya is made only of stones, stones chosen specially and individually tested for their strength at India's foremost geological testing laboratory situated at Kolar Gold Fields. "The stones that have been carefully chosen will last till eternity," says Dr HS Venkatesh, Director of the National Institute of Rock Mechanics (NIRM), Bengaluru, the national facility that helped in testing the stones using a physico-mechanical analysis. The NIRM is the nodal agency to test rocks for Indian dams and nuclear power plants.
"Very specially selected granite, sandstone and marble are the only stones that have been used in the construction of the Ram Mandir," confirms Venkatesh.
The stone blocks of granite, sandstones, and marble used to construct the temple were critically assessed for their integrity and soundness using scientific principles and tools, he added.
It is estimated that a whopping 20,700 large blocks of granite, 32,800 blocks of sandstone and 7,200 blocks of marble have been tested individually and used in the Ram temple, all conforming to Indian Standards Institution or ISI standards.
The grey granites have been used just above the engineered foundation and make the 6.7 meter thick plinth for the temple. "The granites are at least 2,100 million years old and sourced from the southern India from carefully selected mines at Ongole, Chimakurti, Warangal, and Karimnagar," says Venkatesh. These were then transported to Ayodhya and at the mine heads, each block was subjected to modern scientific tests like the Schmidt Hammer to determine the hardness. "All blocks with doubtful quality were rejected at the mine head itself." says Venkatesh.
The super structure of the temple that will be visible to all visitors is made of specially selected sandstone. "Pink Bansi Paharpur stones from Rajasthan have been selected," says Nripendra Misra, chairperson of the temple construction committee of the Shri Ram Janmabhoomi Teerth Kshetra Trust. Around 4.75 lakh cubic feet of this famous sandstone has been sourced, it is learnt. The sandstone is at least 700-1,000 million years old, says Venkatesh. Sandstone is a preferred material since it is soft enough to carve but hard enough to withstand weathering like wind erosion.
"The marble used is white in color and comes from the famous mines of Makrana in Rajasthan," Venkatesh says. Marble has not been used as a load bearing stone but only as a decorative material, especially in the garba-griha or sanctum sanctorum of the temple. The marble is at least 1,450 million years old, cientists at NIRM estimate.
All the rocks were tested for density, porosity, compressive strength, structural strength, tensile strength, water absorption, and modulus of rupture by a team led by Dr A Rajan Babu, who led the rock-testing.
The carved pillars were also subjected to non-destructive testing (NDT) using ultrasonic and infrared thermographic techniques.
"It was an enjoyable and devotional experience to contribute to this one of a kind temple construction project of national eminence," says Venkatesh.
"As far as the rocks are concerned we can guarantee that they will live for more than a thousand years," he asserts.