The Counter-deception Blog

Forging art and antiquities is a game that is, well, ancient. The so-called "James ossuary" is caught in the swirl of charges regarding its authenticity.

Fake Out! How forgers made grime seem ancient.
By Brendan I. Koerner
slate.com
Posted Thursday, Dec. 30, 2004, at 3:45 PM PT

The Israel Antiquities Authority has advised museums worldwide that their
Bible-era relics may be fakes produced by a team of forgers now under
indictment. These forgers are charged with concocting the so-called James
ossuary, which purportedly held the bones of Jesus' brother. According to
the AP's account, they were skilled at creating "ancient grime" that fooled
many scientists into authenticating their wares. How might a forger go about
making grime that seems ancient?

For starters, with a bit of chalk and water. The forgers' key to tricking
the archaeologists was crafting an authentic-looking patina. Like copper or
bronze statues, which develop a green sheen after years of oxidization,
stone slowly builds up a layer of geological soot as the centuries reel by.
This is caused by the chemical reaction of elements like air or water with
the minute traces of metals and other elements within the rock. To the naked
eye, a thick patina is an immediate sign that an artifact is aged.

Yet a skilled forger can fake a stone patina, at least convincing enough to
fool all but the most advanced analysis. In the case of the James ossuary,
for example, it's alleged that the forgers took an authentically old box
that was inscribed simply "James, son of Joseph." According to Avner Ayalon
of the Geological Survey of Israel, who studied the ossuary, the forgers may
have then added the inscription "brother of Jesus" to the end of the
sentence and used a solution of chalk and hot water to create a coating of
calcium carbonate-a substance frequently found in stone artifacts excavated
in and around Jerusalem. On cursory inspection, the patina appeared to be
legitimate. Conventional verification means like ultraviolet light or simple
chemical analysis could not differentiate the patina covering the first half
of the inscription.

Ayalon became suspicious, though, when he tested the patina's isotopic
ratios-that is, the number of oxygen atoms containing 16 protons plus
neutrons versus the number of oxygen atoms containing 17 or 18 protons plus
neutrons.* These ratios are affected over time by an object's environmental
conditions. Ayalon discovered that the portion of the patina covering the
first part of the inscription was marked by an isotopic ratio consistent
with Jerusalem's groundwater. The section covering the latter half, by
contrast, betrayed evidence of having been created at high temperatures,
probably well in excess of 120 degrees Fahrenheit-far above the temperature
of ground water in caves, where ossuaries were stored.

Strategies for crafting a convincing artificial patina can, of course, vary.
Another alleged work of the indicted men was the so-called Jehoash (or
Yoash) tablet, inscribed with what appeared to be proof that it had come
from the 3,000-year-old Temple of Solomon. The tablet initially passed
muster when chemical analysis revealed that trace amounts of carbon within
the rock were, indeed, several millennia old. Furthermore, the patina
featured traces of gold, and the temple was renowned in the Bible for its
overlay of high-quality gold.

But questions arose when further analysis was undertaken and it was
discovered that the patina was imbued with microscopic marine fossils-quite
odd, considering the temple was nowhere near the sea. Then one of Israel's
top archaeologists, Yuval Goren of Tel Aviv University, found that the
patina on the tablet's back was made of silica rather than calcite, which
would have been consistent with Jerusalem's geology. (There were also
several linguistic cues that tipped off researchers, particularly
anachronisms.)

Professor Goren proposed that the inscription had been chiseled onto a slab
from a Medieval castle built by crusaders. A fake patina may then have been
created by crushing up bits of identical stone, mixing the powder with
water, and baking the whole concoction. Charcoal bits stolen from Jerusalem
archaeological digs or university museums could have been added during the
process, as could have specks of gold. It may have been more elegant than
adding silver black to jewelry, a common trick used by charlatans to make
new pieces look old. But it wasn't quite perfect.

Brendan I. Koerner is a contributing editor at Wired and a fellow at the New
America Foundation.