
‘Alexandrian’ glass confirmed by hafnium isotopes - diodorus
https://www.nature.com/articles/s41598-020-68089-w
======
VLM
Its an insider's journal paper so they gloss over what zircons are although
they're the whole point of the paper.

The chemistry of zircons is pretty cool. A non-technical terrible analogy is
they're like nearly indestructible test tubes that bottle up whatever
contaminants are in the area when they initially crystallized and then they
sit there for eternity or until lava melts them (and some lavas aren't hot
enough to melt them, whoa!).

So various natural variations in Hf isotopes by location are bottled up by
zircons, and when melted into ancient glass the glass liquifies at a half or
third the temp required to liquify zircon crystals, so they sit there with
evidence of where the materials came from bottled up for all eternity.

Zircon also shows up in radwaste schemes. Despite mother nature and humanities
best efforts we generally haven't destroyed zircons over centuries, so it
seems a useful strategy to bottle up radwaste in giant zircon crystals.

Weird fact, most zircons are stable at boiling iron temperature. Note I wrote
boiling, not melting iron. Liquid tungsten is hot enough, sure, but not mere
liquid iron.

Its a pity zircons are structurally useless. Of course it would be a recycling
nightmare if they were industrially useful for bulk structures and components.
Interesting sci fi aspect, all the chemists I've talked to are certain that
Pierson's Puppeteer General Products space ship hulls were based on the idea
of industrial zircons as a structural material although in one story those
hulls were proposed to be a carbon fiber analog of zircons or something like
that. A "zircon polymer", should such a magical material exist, would make an
interesting structural material when threads of it were knitted into 3d
shapes.

~~~
jofer
Don't forget that there are zircon grains around today that are nearly as old
as the Earth. There are zircon grains dated at over 4.4 billion years old.
They've survived _a lot_. These are zircon grains that have survived
everything else around them being melted and metamorphosed multiple times,
then eroded, then redeposited, etc. We don't really know anything about the
rock they originally crystallized as a part of, but the individual zircons are
almost indestructible and make it into new rocks as old rocks are destroyed.

They're also massively useful as a "fingerprint" of what rocks eroded to
produce a particular sediment. You can identify things like river drainages
switching through time by what zircons are in sands. (Search for detrital
zircon geochronnology.) It's incredible what you can piece together by looking
at zircon grains!

~~~
isoprophlex
[https://en.m.wikipedia.org/wiki/Hadean_zircon](https://en.m.wikipedia.org/wiki/Hadean_zircon)

Whoa that was a fun read, thanks for sharing about those zircons!

------
bane
A few things struck me when I first went to Rome.

\- How colorful Roman architecture was in its heyday. Some of the preserved
interiors are full of rich wall paintings with some fairly modern abstract
bits in the them. It's nothing like we see today.

\- How much brick the Romans used. I remember wandering around looking at some
ruins and dismissing some walls as "must be some 19th century stuff" only to
realize that those brick walls were the original from a couple _thousand_
years ago.

\- How close Rome was to mass manufacturing. I remember learning for the first
time how many Roman statues were the result of the client choosing a precarved
heroic torso they liked from a dealer, and then an artist producing a suitable
custom bust to fit the headless torso. The two were simply fitted together and
voila, instant statue and less posing time for busy patrons.

\- Roman glassware. The first time I saw it in a museum I passed it by, again
thinking it must be some late 19th century early 20th century stuff. Romans
just had pottery and such didn't they? No! Their tableware would not look too
outlandish sitting at a place setting in a modern context today -- or at least
as suitable flower vases.

~~~
jaclaz
Regarding glasswares Romans were already into mass-manufacturing many items,
once they managed to use mould techniques with blowed glass, common items
became inexpensive:

[https://www.ancient.eu/article/592/roman-
glass/](https://www.ancient.eu/article/592/roman-glass/)

The technique, see page 9 of this (Italian) pdf:

[http://s580172868.sito-web-
online.it/risorse/VetroNotizie_20...](http://s580172868.sito-web-
online.it/risorse/VetroNotizie_2006_11_Moretti.pdf)

allowed for quick producing.

~~~
HarryHirsch
See here a video from the Villa Borg:
[https://www.youtube.com/watch?v=jaODucearU8](https://www.youtube.com/watch?v=jaODucearU8)

Also Ennion:
[https://www.youtube.com/watch?v=yYdwqnvqEi0](https://www.youtube.com/watch?v=yYdwqnvqEi0)

Here is the incredible Bill Gudenrath producing Roman glass:
[https://www.youtube.com/watch?v=xWZh7RXkW0I](https://www.youtube.com/watch?v=xWZh7RXkW0I)

------
fuzzfactor
This is some great geochemical archaeology and fine instrument work from a
well-built team with a strong multidisciplinary operation.

Progress can be achieved like no other when the project leader is the one who
not only has outstanding instrumental expertise, but also performs the
_experiments_ themselves.

Consistently over half a dozen major projects per year, this is high-
performance operation.

If you're not dedicated to taking good care of your instruments, they won't
even function the entire year.

For quantitation we've got one of the expensive benchtop models (and a retired
one to restore), but they've got a _real_ expensive forklift model in
addition, which makes this type of isotope analysis possible.

Only one reason I don't do any geochemistry or archaeology either, just
produce boring old invoiceable paperwork.

------
aardvark291
"our understanding of critical aspects of the ancient glass industry is
fragmentary"

I see what you did there...

