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-   -   "Alexandrian" glass confirmed by hafnium isotopes (http://talk.craftweb.com/showthread.php?t=12640)

Paul Thompson 07-25-2020 11:08 AM

"Alexandrian" glass confirmed by hafnium isotopes
 
(Link to article)

Abstract

Archaeological glass contains information about the movement of goods and ancient economies, yet our understanding of critical aspects of the ancient glass industry is fragmentary. During Roman times, distinct glass types produced in coastal regions of Egypt and the Levant used evaporitic soda (natron) mixed with Nile-derived sands. In the Levant, furnaces for producing colourless Roman glass by addition of manganese have been uncovered, whereas the source of the desirable antimony-decolourised Roman glass remains an enigma. In the Edict of Diocletian, this colourless glass is listed as “Alexandrian” referring to Egypt, but its origin has been ambiguous. Previous studies have found overlapping strontium and neodymium isotope ratios for Levantine and Egyptian glass. Here, we confirm these findings and show for the first time, based on glasses from the ancient city of Gerasa, that hafnium (Hf) isotopes are different in Egyptian and Levantine natron glasses, and that Sb Roman glass is Egyptian. Our work illustrates the value of Hf isotopes in provenancing archaeological glass. We attribute the striking difference in Hf isotopes of Egyptian versus Levantine glasses to sorting of zircons in Nile sediments during longshore drift and aeolian transport along the south-eastern Mediterranean coast leaving behind a less juvenile fraction.

Pete VanderLaan 07-25-2020 05:47 PM

we should not leave out effusive bullshit from the northern Hemisphere. It's had a permanent effect.

John Croucher 07-25-2020 11:25 PM

It's interesting that, just as now in the 21st century glassblowers want to buy cullet, no latter how far it's got to be transported, so did glassmakers in Roman empire times. Most glass shops bought color and cullet from only 2-3 sources in the Levant and Egypt. The vessel makers rarely made their own glass.
The cullet was mostly melted close to good glass sands in large tanks. Very large tanks. The furnaces found at Bet Eli'ezer near Haifa in modern day Israel for instance, melted 8-10 tonne slabs of glass in situ and then the furnace was knocked down and the glass broken up into chunks which were shipped all over the Mediterranean.

Pete VanderLaan 07-26-2020 11:00 AM

So, somewhere out there was "The Tigris and Euphrates" Color rod company. Who knew?

I am continually amazed at how far melters would go and how they knew in that time period what was really important.

Stibnite? Really, how did they ever know. They were going to NE Turkey and to Iraq to get it. (Stibnite yields Antimony) . I have several Corning publications on ancient glass analysis and its simply remarkable how well balanced those ancient glasses were.

Charles Friedman 07-26-2020 12:14 PM

If you are interested in the history of glass. This is a good read on old glass making and it's history. "Glassmakers: An Odyssey of the Jews : The First Three Thousand Years" by Samuel Kurinsky.
same with "Conciatore" The life and Times of 17th C Glassmaker - Antonio Neri. He printed the first book on glassmaking.

PS
I have missed doing glass so much I have resorted to "Mini chocolate-chips- roll-ups on a roasted marshmallow".

Art Freas 07-27-2020 06:42 PM

Quote:

Originally Posted by Pete VanderLaan (Post 148354)
So, somewhere out there was "The Tigris and Euphrates" Color rod company. Who knew?

Phillipus of Olympus Vitreis Quis Color Virga?

Pete VanderLaan 07-27-2020 07:57 PM

Cheap imitator!!

John and I are starting to go around on the very subject. I love talking to John. If it's affordable, find "glass of the Alchemists" which Corning produced as a coffee table book about 20 years ago, maybe longer.

Pete VanderLaan 07-27-2020 07:59 PM

Quote:

Originally Posted by Charles Friedman (Post 148355)
If you are interested in the history of glass. This is a good read on old glass making and it's history. "Glassmakers: An Odyssey of the Jews : The First Three Thousand Years" by Samuel Kurinsky.
same with "Conciatore" The life and Times of 17th C Glassmaker - Antonio Neri. He printed the first book on glassmaking.

PS
I have missed doing glass so much I have resorted to "Mini chocolate-chips- roll-ups on a roasted marshmallow".

****
Thanks Charles, I have Neri but the other has been elusive at a fair price so far.

Tom Fuhrman 07-28-2020 12:34 PM

I remember when Kurinsky gave a presentation at a GAS conference on his book. very interesting.

Hugh Jenkins 07-28-2020 06:04 PM

I got a copy of Kurinsy several years ago for almost the cost of shipping. It is a deadening read actually.Three months of self isolation and still not done. Three or four pages at a time is enough. But recalling his GAS presentation almost accusing everyone in the audience of intentional ignorance, it is interesting to read the historical information, much of which has been there, at least being compiled in readable form. Our adulation of Venice and the prominently advertised Egypt-ology, has overshadowed most of what came before that. Historical record was scarce 3000 years ago.
This story almost excludes the sociopolitical (ie warfare, conquest) that was coincident and makes it a little hard to overlay with the world history we were all taught, but puts some context into why glass was slow compared to ceramics, bronze and iron around the world. The pyrotechnology had to develop with wood as the major fuel.


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