A lot of my discoveries seem like tall tales... here's some evidence now
March 1, 2017 11:14 AM   Subscribe

47 ingots of a copper (80%) and zinc (20%) based alloy with small traces of lead and nickel, two Corinthian helmets, archaic amphorae and a Massaliote round-bottom flask (ie., from the ancient Greek colony of Marseilles in France), have recently been recovered off the coast of Bulala, near the ancient Greek colony of Gela, in southern Sicily. This is the second recovery of a collection of this ancient alloy, the first brought up 39 ingots in 2015, when the metal was first called orichalcum, and with it came references to Atlantis. But what is orichalcum, a mined metal or an alloy?

Plato's Critias dialog includes an early reference to orichalcum, in his recounting the greatness of Atlantis:
...they dug out of the earth whatever was to be found there, solid as well as fusile, and that which is now only a name and was then something more than a name, orichalcum, was dug out of the earth in many parts of the island, being more precious in those days than anything except gold.
But by the time of the Roman empire, orichalcum was understood to be a metallic substance resembling gold in color, but very inferior in value. Edward Polehampton summarized that it was "the Brass of the Ancients" (Google books preview), implying that it was a manufactured alloy, not a mined metal at all. This idea has been supported by numismatists for some while, who have cited stories of coins of orichalcum being used alongside brass in India (Google books preview). For modern numismatics, orichalcum is the name given to a brass-like alloy of copper and zinc used for the Roman sestertius and dupondius.

Still, anything associated with Atlantis still captivates and intrigues, as seen with the numerous references to orichalcum in a range of modern media (TV Tropes). And if you want to make your own ring of orichalcum, Mat Brown shows you how he does it in a 9 minute YouTube video (no narration, all steps described in on-screen text).
posted by filthy light thief (19 comments total) 22 users marked this as a favorite
 
[The title is a truncated quote from the 1992 computer game Indiana Jones and the Fate of Atlantis]
posted by filthy light thief at 11:16 AM on March 1, 2017 [7 favorites]


orichalcum was understood to be a metallic substance resembling gold in color, but very inferior in value

This made me super curious because that's a fair description of Jewler's Brass which runs 85% copper/15% zinc though I guess covers anything in that general range.

Quite the post!
posted by Ogre Lawless at 12:17 PM on March 1, 2017 [2 favorites]


As luck would have it I've been reading The Disappearing Spoon (excellent read). In a section on transition metals he talks of a Phrygian kingdom whose metallic deposits were unusually high in zinc and produced a natural brass that was highly prized because it was more gold-like than bronze. Modern tests have reproduced this result from the local ores. The monarch's name was Midas...
posted by jim in austin at 12:22 PM on March 1, 2017 [12 favorites]


Ogre Lawless, thanks for that reference!

jim in austin, that's fascinating!
posted by filthy light thief at 1:27 PM on March 1, 2017 [1 favorite]


J'Zargo believes the orichalcum mines were just one of the many totally accurate aspects of Skyrim.
posted by ROU_Xenophobe at 1:48 PM on March 1, 2017 [4 favorites]


metallic deposits were unusually high in zinc and produced a natural brass

I meant to write, this gives credence to orichalcum being mined and made, which is really interesting.
posted by filthy light thief at 2:33 PM on March 1, 2017 [1 favorite]


So, I'd been meaning to get an account here for ages - literally years - and the day I do is also the day someone makes a post which links to one of my videos.

The ring I make in that YT video is a formulation I came up with which is vaguely close to what might be one version of orichalcum. It's surprisingly nice to work with, often non-standard alloys are either very hard (or very soft) or weirdly brittle or other undesirable thing. Orichalcum also seems to tarnish a bit less than some other gold-looking mixtures, although obviously it still discolours because, well, it isn't gold. I've since revised my recipe to have less zinc in as it's a bit prone to boiling before everything else melts and inhaling zinc isn't the greatest thing to do. Replacing zinc with tin hasn't made much difference in the appearance and it's a lot safer for me.

Ancient and unusual alloys are an interest of mine, I've also made electrum (gold/silver), shibuichi (silver/copper), Corinthian bronze (silver/copper/tin) and am hoping when I get time to try some of the traditional Japanese copper/gold alloys, which have interesting properties for taking patinas.
posted by auntie-matter at 2:49 PM on March 1, 2017 [45 favorites]


auntie-matter : Links! Links! And oh, welcome to MetaFilter...
posted by jim in austin at 3:02 PM on March 1, 2017 [2 favorites]


I've also made electrum (gold/silver)

I thought that was something D&D made up
posted by thelonius at 3:44 PM on March 1, 2017 [2 favorites]


filthy light thief: "[The title is a truncated quote from the 1992 computer game Indiana Jones and the Fate of Atlantis]"

Elsa: What's this?
Indiana Jones: Ark of the Covenant.
Elsa: Are you sure?
Indiana Jones: Pretty sure.
posted by Chrysostom at 7:08 PM on March 1, 2017 [5 favorites]


auntie-matter, welcome! Thanks for the well-made video, and additional information here!
posted by filthy light thief at 7:54 PM on March 1, 2017


So, I'd been meaning to get an account here for ages - literally years - and the day I do is also the day someone makes a post which links to one of my videos.

Oh hey, why the 5% silver?
posted by sebastienbailard at 10:00 PM on March 1, 2017


Oooh, links. Righty. I was a bit unsure because I didn't want to be accused of pimping my stuff but as you asked..

Electrum rings making process, and also video of the same rings in different lights. The video doesn't show it well, they appear various shades of silver, yellow, even faintly green in different lighting conditions. Electrum was fairly common in the Ancient world, often used as coinage in part because your gold goes quite a lot further when you dilute it with silver. The other part being that it occurs naturally in the ground as well being manmade, and without some fairly Heavy Chemistry it's very hard to purify into fine silver and gold.

Shibuichi ring, which is 50/50 silver/copper, although that's not a very traditional ratio, I like it. This stuff tarnishes to a beautiful silver-grey colour. On the subject of tarnish, the orichalcum ring in the video above looked like this after a few weeks.

Also, Corinthian Bronze, an alloy occasionally referred to in antiquity, looks like this, that's a mixture of silver/tin/copper at (in this instance) a 2/2/6 ratio. Which I think technically makes it a brass not a bronze, but I always get those mixed up. I did recently make a tiny bronze Saxon sword as a retirement present for a friend who is a fan of archeology.

As for the silver in the orichalcum, I think that was because I read somewhere there should be a 5% iron in there but the first time I tried making the stuff, it did the weird thing which alloys can do, where it has a melting point higher than it's constituent parts. Melted it all together then it went solid and my torch at the time couldn't touch it. I really wish I'd documented my messing about with orichalcum a bit better.

I'm making some orichalcum for a customer today (or maybe tomorrow, depends how things go), I guess I should set my camera up... (and write down what I'm doing)
posted by auntie-matter at 3:12 AM on March 2, 2017 [8 favorites]


I was reading about Argentinium, geranium 1.2% germanium-doped silver, where the geranium germanium dioxide forms a protective layer:
Investigations using a Transmission Electronic Microscope (TEM) have shown that a thin dense layer of transparent germanium dioxide (GeO2) forms on the surface of Argentium silver alloys when they are exposed to oxygen. It is this layer that gives Argentium silver its protection against tarnish and firestain. The germanium dioxide layer is self-regenerating; if it is worn off by abrasion, it will reform. Stainless steel uses chromium oxide for protection in a similar way.
-(wikipedia)

and I wondered if it would work to keep copper alloys shiny. Apparently
Germanium is also used in electroplating and in the production of alloys, one of which, germanium-bronze, is characterized by high corrosion resistance.
-Encyclopaedia of Occupational Health and Safety:
posted by sebastienbailard at 4:50 AM on March 2, 2017 [2 favorites]


auntie-matter, thanks for sharing more information about your experiences with ancient and unusual alloys! k5.user made you a MetaTalk welcoming thread.
posted by filthy light thief at 7:46 AM on March 2, 2017 [1 favorite]


sebastienbailard that's an interesting idea. I may order some geranium germanium and see what happens when mixing it into a copper alloy..
posted by auntie-matter at 9:24 AM on March 2, 2017


Plato also said that people used to be joined in pairs of two and were round and travelled by rolling from place to place
posted by thelonius at 11:15 AM on March 2, 2017


Ooh, a metallurgy post! *drools*
Awesome links here, and welcome, auntie-matter.

Oh, and the way I keep brass and bronze straight is that they use the opposite letter from their non-copper constituent. So, brass, uses zinc (Zn) and bronze uses tin (Sn). It's exactly the opposite of what you might expect from the spelling of the two.
posted by blurker at 1:14 PM on March 2, 2017 [1 favorite]


One author might be consistently misspelling this as "orilachrium" maybe? Or maybe that's the intentional name of a fictional metal.
posted by XMLicious at 6:45 PM on March 20, 2017


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