Patina Fingerprinting

Patina fingerprinting refers to the application of an isotope test to a layer of patina. An isotope test will determine the isotopic signature, or chemical fingerprint, of a chemical compound, and can assist archaeologists as a dating method of artifacts (such as the ossuaries found in the Jesus tomb). This in turn can also determine the authenticity of an artifact. An isotope test will assist in determining the chemical make up of patina.

What is Patina?

"Patina" is an umbrella term used by archaeologists to describe a variety of different types of thin film that accumulate on the surface of artifacts. Patina formation can result from different types of chemical reactions. These are determined by factors such as the materials that make up an artifact, the environment to which it is exposed including the degree of moisture or humidity in the air, and the soil types in the surrounding area.

These variables can also determine how quickly patina will form on a given artifact. For example, some patinas will from very quickly once an artifact is stationed in a given area, and others are more easily removed by chemical treatment.

Patinas in the Jerusalem Region

The landscape of the Jerusalem region is quite varied, resulting in a large differentiation between the types of patina formation that take place. For example, a stone ossuary buried in a Jerusalem cave might be exposed to dust from the area's red soil, rich in iron and calcium. The moisture of the cave may also affect chemical reactions. Alternatively, an artifact buried in the volcanic soils, which is often the case in the region surrounding the Sea of Galilee, will likely produce different results.

Patina Fingerprinting: Isotope Testing

An isotope is any variation of the same element with a different atomic mass. The number of neutrons will be different in an isotope of a neutral element such as oxygen. The different masses of an element's isotopes can affect chemical reactions.

An isotope analysis will identify the distribution of stable isotopes and chemical elements of a compound. Isotopic analysis of artifacts is usually performed to determine the date of an object and will determine isotopic ratios of organic material (carbon and oxygen), minerals (potassium-argon), and ceramics (thermo-luminescence dating).

The patina found on a given ossuary can be compared to other patina signatures (isotopic compositions) of ossuaries from the same period to confirm dating of the artifact. The patina test of several artifacts found together in a given location can help determine their age in relation to one another. This is especially important to sites containing several layers of civilization.