Created at the Technion, the Tanach ("Old Testament") is the size of a grain of sand. An article about it from 2007 describes it:
I hope the Pontiff doesn't lose it at the airport.Out of Zion has come the world’s tiniest Bible, engraved in gold on silicon, to illustrate the science of nanotechnology.
More than 300,000 words and 1,200,000 letters, including vowels have been placed on less than half a square millimeter, allowing the tiny Torah to fit inside the first dot of the first letter of a traditional Torah scroll.
“We took a piece of silicon and evaporated a very small layer of gold over it, about twenty nanometers thick,” explained Ohad Zohar, a Ph.D. student at the Technion, on IsraelNational Radio’s Yishai Fleisher Show. A nanometer is about a billionth of a meter.
“We then used a focused ion beam to inscribe the Biblical text on it,” Zohar said. “What the focused ion beam does is shoot gallium ions, focusing the charged particles on the substrip [of gold]. It digs little holes and each hole is a pixel for whatever picture you would like. In our case this is the Tanach [Five Books of Moses, Prophets and Writings –ed.].”
Of course, the Vatican will now need to purchase a scanning electron microsocope to actually read it.