With their vacant eyes and enigmatic, toothy expressions, the 9,000-year-old stone masks from the area around the southern Judean desert are among the region’s most compelling and distinctive artifacts. Adding to that is their rarity: Only 15 examples are known to exist. So, when the Israel Antiquities Authority (IAA) recently announced the discovery of a sixteenth stone mask, it grabbed the attention of archaeologists and the public alike—but also revived a simmering discussion on the authenticity of these unique objects.

The stone mask was recovered several months ago by the authority’s Theft Prevention Unit, according to an IAA press release. A subsequent investigation led archaeologists back to the “probable archaeological site in which the mask was originally found,” near