Secrets of ancient pottery revealed

Jun. 24, 2013

CLARC objects on display

Alison Crandall's chemical analysis of five CLARC objects (displayed inside the circle of stones) is part of an exhibit currently on display at the Mandel Center for the Humanities.

By David Levin

Although some archaeological finds—like the jars containing the Dead Sea Scrolls—have changed the course of history, the vast majority of pottery from ancient Israel is far more mundane. Many of the artifacts unearthed at dig sites around the region served as containers for food or cosmetics, utilitarian items that, once excavated, often gather dust in museum collections.

As Alison Crandall '13 is discovering, however, these overlooked artifacts can still provide valuable information about the ancient world.

Crandall, a dual major in classical studies and chemistry, spent this past spring performing complex chemical analyses on five objects from Brandeis’ Classical Studies Artifact Research Collection (CLARC), named in honor of primary donor Eunice M. Lebowitz Cohen, a trove of more than 800 pieces from antiquity that have been donated to the university over the past few decades.

Under the mentorship of Andrew Koh, associate professor of Classical Studies, Crandall removed small fragments from several of the objects, then worked with scientists at Boston’s Museum of Fine Arts to embed the samples in plastic resin. The lab then sliced each sample into sections thinner than a human hair to examine them under a scanning electron microscope, a process that revealed the individual grains of clay that made up each pot.

"The microscope gives you a grayscale image of the sample," says Crandall. "You can actually tell by the shade of each grain what it’s made of —the darker the color, the heavier the molecular mass of the material."

Based on the percentage of each mineral in the sample, she says, it’s possible to match the clay to soil from specific regions, helping pinpoint the artifacts’ origins. Of the objects Crandall analyzed from the CLARC collection, two appear to be made from clay collected near Tel Hadar, an ancient settlement on the shore of the Sea of Galilee in modern day Syria.

Crandall also used a method called "organic residue analysis" on some of the CLARC objects to search for remnants of the jar’s original contents that had embedded into the porous clay fabric. In many cases, the substances were too badly decomposed to tell what was inside, but Crandall was still was able to tease out telltale clues in the lab.

A long, thin jar of unknown origin showed traces of caproic acid—a molecule found in honey, a common sweetener in antiquity. A smaller jar, she says, revealed the presence of styrax, a pungent tree sap used in making perfumes.

"The work Alison is doing under the mentorship of Dr. Koh with some of our CLARC objects is truly cutting edge," says Ann Koloski-Ostrow, associate professor and chair of the Department of Classical Studies and principal curator of the CLARC collection. "This sort of analysis can help us identify commodities and trade routes in the ancient Mediterranean, which has the potential to write or rewrite history. What she’s finding is very exciting."