It is never possible to establish 100 percent authenticity. No matter how many tests you apply, there may be another test that would reveal that an object is a forgery. This is true even of objects found in professional excavations. Theoretically, the finds could be salted. Indeed, some scholars have charged that that is the case with the famous Tel Dan inscription excavated by Israeli archaeologist Avraham Biran, and the Ekron description excavated by Trude Dothan of Hebrew University and Seymour Gitin of the Albright Institute in Jerusalem.