In June 2006, Harry M. Jol, from the University of Wisconsin–Eau Claire, performed measurements with ground-penetrating radar (GPR) to determine the depth of the stone.
The calculated weight of the stone block is of 250–300 tonnes, based on Jol's measurement.
[5][6] A previous estimate of the stone's depth was 16.5 metres (54 ft), a multiple of the GPR measurement, and led to a calculated total weight of 567 tonnes.
[5][6] The Western Wall Heritage Foundation (WWHF) website indicates, as of March 2020, an estimated depth of 2–4.6 metres (6.6–15.1 ft), with an estimated weight of "several hundred tons",[1] thus moderating its former estimated weight of 517 tonnes (570 short tons);[7] The stone is located in a section of the Western Wall (in the broader meaning of the term) north of Wilson's Arch, below ground level, and can be accessed through the Western Wall tunnels.
It is part of the "Great Course", a name used by the WWHF for the tallest and longest course (layer of stones) of the Western Wall.