The question of authenticity naturally arises in connection with any artifact that is without provenance and is acquired on the antiquities market.

The Ahaz bulla was one of a group of more than a hundred bullae that I published recently.3 The surfaces, the edges, the cracks and the reverse of each of them—whether in good condition or burnt and damaged—were examined under a powerful (×40) microscope. We also took both color and black-and-white photographs of these bullae and enlarged them to 40 times the original image, which allowed for careful examination of the weathering of the seal.4 I can only repeat what the late Nahman Avigad, the doyen of seal scholarship in Israel, wrote when he published a group of more than 250 bullae from the antiquities market: “There was no reason to suspect their authenticity, and I seriously doubt whether it would be possible to forge such burnt and damaged bullae.”5

All the bullae in the group I published had suffered from corrosion. Crystals of different sizes and shapes protruded from the bullae. These crystals often grew in the clay, toward the outside, causing cracks and breakages in the surface. Corrosion and crystals were also present in cracks made when the seals were impressed onto the lumps of clay in antiquity. These crystals were not visible on recently damaged surfaces. It would have been difficult if not impossible for a forger to create this corrosion and crystal growth. These conditions take centuries to develop.

What was not found was also telling: No wires, hairs or other organic materials were detected in or on the clay. They probably existed in antiquity, when the bullae were made, but they decomposed and vanished over time. They would probably have been present on recently manufactured bullae.

Two bullae that had been fired and were in a poor state of preservation were sent to two different laboratories for thermoluminescence tests. Both laboratories reported that the bullae were ancient.

The Ahaz bulla has been examined by a number of preeminent scholars, among them Frank Moore Cross, André Lemaire, Pierre Bordreuil, P. Kyle McCarter, Jr., Wilfred D. Lambert and Gabriel Barkay. All agree that the bulla is genuine.

Finally, look at the photograph above. Notice the dot-and ring-shaped crystals growing on the surface. There is an especially large white crystal above the letter alef. This crystal grew from inside the clay toward the outside, causing a crack and breakage in the surface. This is well-nigh conclusive evidence as to the authenticity of this extraordinary bulla.

For all these reasons, we can conclude the bulla of King Ahaz is genuine and not a forgery.