Investigation of a mummy bead “coating”

While we continue to work on the conservation of PUM I‘s remains, we also have been taking this opportunity to carry out some analysis on the residues and substances preserved on his wrappings and on the beads that once made up his beaded burial shroud.

Since the last time we wrote about these beads, we have recovered even more in the conservation process; we now have a total of 35 beads – all either tubular or circular in shape. As we wrote about in a previous post, all of the beads are covered with concretions, mostly a brown, waxy material. Here is an image of one of the beads before cleaning, and after partial exploratory cleaning, revealing the beautiful blue color of the bead:

A tubular bead before (left) and after (right) exploratory cleaning to remove the residue on the surface ( 10X magnification)

A tubular bead before (left) and after (right) exploratory cleaning to remove the residue on the surface ( 10X magnification)

This material does not appear to be dirt or accumulated debris from the mummy. But, it can be removed rather easily from the beads, especially with the help of some mineral spirits, which suggested to me that it is some sort of wax.

Based on this information, I was suspecting that either this material was related to a substance applied to the beads to help the beaded shroud stay in place at the time of burial (but we have yet to locating any research supporting this theory – it was more common to sew or tie these beaded shrouds in place) or that it is related to a substance applied to the shroud at the time of discovery, to assist with the removal of the shroud.

In conservation, when it comes to investigating unknown, likely organic substances, there are several analytical techniques that can be helpful. One of these techniques is Fourier-transform infrared (FTIR) spectroscopy. FTIR works by exposing a sample to infrared radiation, which causes the sample to selectively absorb radiation, depending on the molecules present. The individual peaks in the resulting absorption spectrum can be analyzed or the spectrum can be compared to reference spectra to help characterize or identify a material.

We provided a small sample of our “bead coating” to Gretchen Hall, a consulting scholar in the Biomolecular Archaeology lab here at the museum. She ran the sample for us and provided the resulting spectrum and interpretation. Here is the spectrum produced by our sample:

E2813A_FTIR_beadThis spectrum shows that the sample is mostly organic as evidenced by the dominant peaks in the 2900 cm-1 region which are characteristic of C-H bond stretches.  In addition, there were many peaks in the “fingerprint” 1800-1000 cm-1 region where various organic molecules absorb. The absorption around 1730 cm-1 (due to C-O double bond stretches) suggests organic acids are present, possibly from resins or beeswax. Both of these families of compounds would also have bands around 1470 (a O-H bending absorption) which are seen in our sample. Importantly, the sample also shows a strong band around 720-730 cm-1 (due to the C-H in long hydrocarbon chains) which is only present in beeswax.

For comparison, here is our bead coating sample spectrum displayed just below the spectrum for a standard beeswax:

E2813A_FTIRBased on this analysis, our “bead coating” sample likely contains some beeswax, which is consistent with our observations of the solubility and consistency of the material as well. It is known that beeswax was used in ancient Egypt – as an adhesive, a sealant, a binding medium, and in the mummification process. Bees were considered by the Egyptians to be precious insects with magical and economic prestige, and these values would have extended to their wax (Ikram and Dodson 1998).

For a more definite identification of our sample, the next step would be to analyze the material using gas chromatography–mass spectrometry (GC-MS).

Special thanks to the Biomolecular Archaeology Lab and Dr. Gretchen Hall for running this sample and providing the analysis.

 

More about those beads

Hello fellow readers! My name is Melissa Miller and I am pleased to say I recently began interning in the Artifact Lab here at the Penn Museum. I am currently a junior at the University of Delaware studying art conservation and anthropology. Needless to say when I heard about the In the Artifact Lab project, I jumped at the opportunity to help out in any way I could. Who wouldn’t love the opportunity to work with 4,000 year old human remains and funerary objects?

Melissa working at the binocular microscope, as viewed from outside of the lab

So far I have spent my first two weeks here doing everything from making support cushions for PUM I’s chest wrappings to making impressions of scarab beetle amulets. Currently, I am examining the beads Molly and the other conservators found in PUM I’s coffin and remains. There are two kinds; tubular and circular. Molly also pointed out to me several areas on the leg and face wrappings of PUM I where there are distinctive impressions of beads in a diamond shaped pattern. This has led us to believe that PUM I had a beaded shroud! Beaded shrouds became popular in the 25th dynasty and continued until the Roman period, and both men and women have been found with these decorations.

Being buried with a beaded shroud would have been very expensive due to cost of materials and labor, and imitations were sometimes made by painting the diamond pattern on the mummy or with a net of knotted string. It is evident, however, that PUM I had a real beaded shroud, which indicates that he was probably wealthy in his lifetime. This surprised me because PUM I is in pretty poor condition and his coffin (which admittedly may not be his original burial case) has little to no decoration.

Three tubular beads recovered from the bottom of PUM I’s coffin

The beads themselves, especially the tubular beads, are encrusted with some mysterious substances and soil particulates. On some of the larger tubular beads, there is a white crystalline substance on the exterior – likely salt. Were it not for small sections on the tubular beads without this encrustation it would be difficult to see the material underneath. The material below is glassy and dark blue in color. This leads me to think that they are made of Egyptian faience, which is defined as a glazed, non-clay ceramic. To me that means that faience is a sort of cross between ceramic and glass technology. The smaller beads also appear to be faience, but in different colors, including this red bead:

As seen in the image above, some of the beads also have a granular, slightly waxy, light-dark brown substance on their surfaces-this mysterious substance is also present in some areas on the surface of PUM I’s wrappings. It can be removed rather easily from the beads, especially with the help of some mineral spirits, and as you can see it tends to come off in substantial chunks.

There are at least a few possible scenarios that would explain its presence.

1) It could have been a part of the technology of the time to adhere the beads to the mummy. In fact, there is 1 circular bead adhered/stuck to the surface of PUM I’s wrappings, which we found after some initial cleaning! However, it seems to be stuck on in kind of a strange location, and we are finding that it was more common to sew or tie these beaded shrouds in place.

A red circular bead stuck to the linen on the side of PUM I’s chest

2)  It could be the remains of a wax or other adhesive method that was known to be used by Petrie, and likely other archaeologists, to fix the beads in place during excavation and recovery. As was usually the case, their original thread had long since disintegrated, so this method would allow the beads to be removed from the mummy in one piece, without losing their organization. To compare, we examined some beads in storage that are stuck together with wax-they were most likely acquired this way.

Beads stuck together with wax – note the dark, shiny appearance of the wax, quite different from what we’re seeing on PUM I’s beads.

3) The substance may be related to a material intentionally applied to the mummy at the time of mummification.

4) The substance accumulated sometime after burial.

As of right now I am not sure what this substance is and what purpose it may have served, but Molly and I will be investigating the beads and this mystery further. I will keep you updated as we learn more!

 

Traces of a beaded shroud

Holiday lethargy? Blustery, wintery weather? No matter-it’s business as usual this week in the Artifact Lab. I really enjoy my job, so I don’t feel like I need any extra motivation to come to work, but it helps that this week I’m working on a pretty interesting recent discovery-something that we found following the removal of PUM I from his coffin last week (see our earlier blogposts on this).

Action shot of our conservation team lifting PUM I from his coffin

PUM I is an unidentified individual, who, until last week, was lying in his rectangular wooden coffin. He had been removed before, for autopsy in 1971/72 (the details are a bit sparse), and his body has been significantly disturbed, cut into, and many of his internal remains are now removed from his body. Needless to say, he doesn’t look his best, and I assumed that any associated burial items were long gone by now. Our hope is that CT-scanning will reveal anything that may have been included or left behind in his wrappings that wasn’t disturbed through this previous work.

So we were pretty surprised when, after lifting his body from the coffin, we found a small bead on the bottom of the coffin, and then another, and now we have recovered 21 small beads. Some of these beads are tubular and others are circular, all with a hole through the center.

20 of the beads found in PUM I’s coffin (shot taken before the 21st bead was found)

Having the mummy out of the coffin also allowed us to examine the wrappings much more closely-it is now evident that there stains and impressions on the wrappings that show a diamond-shaped pattern:

The diamond-shaped pattern visible on the surface of the linen wrappings

This diamond-shaped pattern is a typical design for many beaded shrouds-we have a portion of a beaded shroud here on exhibit in the museum which has this pattern. You can see a photo of this object, along with more information, on our online collections database.

Finally, we returned to look at some old x-rays (from 1932) that we recently had scanned from the museum archives, which showed that the beads were indeed once lying on the wrappings.

1932 X-ray of PUM I. The beads appear on the film, indicated here with red circles.

Looks like the beads that we just found were part of a beaded shroud that once covered PUM I’s wrappings. THIS IS VERY EXCITING!

We will continue to examine these beads to determine what they are made of-they are definitely made of a glassy substance-probably faience. We are also carefully documenting the impressions on the linen wrappings so that we can try to reconstruct what the beaded shroud may have looked like. We will provide updates as we learn more.