[HN Gopher] Medieval Africans had a unique process for purifying...
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       Medieval Africans had a unique process for purifying gold with
       glass (2019)
        
       Author : mooreds
       Score  : 126 points
       Date   : 2025-06-06 22:21 UTC (1 days ago)
        
 (HTM) web link (www.atlasobscura.com)
 (TXT) w3m dump (www.atlasobscura.com)
        
       | gregschlom wrote:
       | This made me realize that I have absolutely no idea what was
       | going on in Africa during medieval times (and only a sliver of an
       | idea in Europe).
        
         | jihadjihad wrote:
         | Mansa Musa is totally worth reading about, as are philosophers
         | etc. like Ibn Khaldun and others (Ibn Khaldun wrote about Mansa
         | Musa's pilgrimage, wealth, etc.).
         | 
         | There was a lot going on in medieval Africa, I wish I had some
         | good sources, if anyone knows any I'd be interested in
         | expanding my knowledge as well!
        
           | petepete wrote:
           | There are episodes of In Our Time on The Empire of Mali (incl
           | Mansa Musa) and Ibn Khaldun
           | 
           | https://www.bbc.co.uk/programmes/b06kgggv
           | 
           | https://www.bbc.co.uk/programmes/b00qckbw
        
           | jorgen123 wrote:
           | The wikipedia page about the Mali Empire [1] has a few books
           | in the Further Reading section. This one looks promising:
           | African Dominion: A New History of Empire in Early and
           | Medieval West Africa [2]
           | 
           | [1] https://en.wikipedia.org/wiki/Mali_Empire
           | 
           | [2] https://www.goodreads.com/book/show/34928286-african-
           | dominio...
        
         | KolibriFly wrote:
         | Same here, most of what I learned growing up barely touched on
         | African history beyond Egypt or colonialism. Stuff like this
         | really highlights how much was going on
        
       | teleforce wrote:
       | Fun facts, Mansa Musa (Musa Keita) who's king in Mali Empire in
       | Western Africa is the richest person ever lived [1].
       | 
       | It's reported that he unintentionally disrupted Eqyption economy
       | for at least ten years. He did that by spending and giving
       | charity in gold enroute to pilgrimage or Hajj in Mecca while
       | staying about 3 months in Egypt. Allegedly he had hundred camels
       | in towing, each camel carrying hundreds of pounds of pure gold.
       | Pilgrimage to Mecca is the journey that every Muslim has to make
       | once in a lifetime if they can afford it.
       | 
       | [1] Mansa Musa: The richest man who ever lived (105 comments):
       | 
       | https://news.ycombinator.com/item?id=19350951
       | 
       | [2] Mansa Musa:
       | 
       | https://en.wikipedia.org/wiki/Mansa_Musa
       | 
       | https://news.ycombinator.com/item?id=19350951
        
         | opo wrote:
         | As your wikipedia link states:
         | 
         | >...While online articles in the 21st century have claimed that
         | Mansa Musa was the richest person of all time,[91] historians
         | such as Hadrien Collet have argued that Musa's wealth is
         | impossible to calculate accurately.
         | 
         | We don't know the exact wealth of Manda Musa and there really
         | isn't a good way to compare wealth between different eras. Even
         | in the same general timeframe, wouldn't the khanates of the
         | mongol empire be considered more wealthy?
        
           | teleforce wrote:
           | Nobody really know for sure to be honest but he's most
           | probably one of the top ten.
           | 
           | The linked BBC article in the HN post has the list for top 10
           | richest man in history with Mansa Musa at the very top but
           | Shah Jahan the Mughal Emperor who's the owner of Taj Mahal is
           | not even in the list [1].
           | 
           | The 10 richest men of all time:
           | 
           | 1) Mansa Musa (1280-1337, king of the Mali empire) wealth
           | indescribable
           | 
           | 2) Augustus Caesar (63 BC-14 AD, Roman emperor) $4.6tn
           | (PS3.5tn)
           | 
           | 3) Zhao Xu (1048-1085, emperor Shenzong of Song in China)
           | wealth incalculable
           | 
           | 4) Akbar I (1542-1605, emperor of India's Mughal dynasty)
           | wealth incalculable
           | 
           | 5) Andrew Carnegie (1835-1919, Scottish-American
           | industrialist) $372bn
           | 
           | 6) John D Rockefeller (1839-1937) American business magnate)
           | $341bn
           | 
           | 7) Nikolai Alexandrovich Romanov (1868-1918, Tsar of Russia)
           | $300bn
           | 
           | 8) Mir Osman Ali Khan (1886-1967, Indian royal) $230bn
           | 
           | 9) William The Conqueror (1028-1087) $229.5bn
           | 
           | 10) Muammar Gaddafi (1942-2011, long-time ruler of Libya)
           | $200bn
           | 
           | [1] Is Mansa Musa the richest man who ever lived?
           | 
           | https://www.bbc.com/news/world-africa-47379458
        
             | jl6 wrote:
             | Mansa Musa's headline story is that his spending caused
             | inflation in Egypt. I understand that estimate of Augustus
             | Caesar's wealth is based in part on him considering Egypt,
             | in its entirety, to be his personal possession. It feels
             | like "owning the whole country" should probably outrank
             | "causing inflation in that country", it's probably
             | meaningless to try to compare across such vast gulfs of
             | time and place.
        
               | notahacker wrote:
               | Musa had an empire too, one that possessed so much gold
               | that his holiday tips devalued the principal store of
               | wealth in foreign countries. Agree the comparisons aren't
               | particularly meaningful; a lot depends on whether your
               | consider having lots of gold to show off with to be more
               | valuable than building an industrial empire, or even
               | owning a bunch of now-common consumer goods and having
               | access to healthcare more impressive than anything
               | Augustus or Musa bought
        
             | LunaSea wrote:
             | Aren't Bezos, Musk, Gates & co richer the first half of the
             | people on the list?
        
               | flohofwoe wrote:
               | Not until one of them buys the entire US armed forces,
               | installs himself on the throne in Washington and declares
               | all of California his own personal property - just to
               | draw a parallel to the number 2 spot ;)
        
               | euroderf wrote:
               | Soon.
        
               | DonHopkins wrote:
               | Democracy Dies in Richness.
        
               | pelagicAustral wrote:
               | Only for 50% of the population
        
               | rayiner wrote:
               | The fact that none of them could come close to doing that
               | aptly illustrates why they're not nearly as wealthy as
               | those in the past.
        
             | saagarjha wrote:
             | fwiw Mughal[?]Mongol
        
             | bernds74 wrote:
             | Some guy once famously noted that wealth is not measured in
             | gold or silver, but in goods and services. Mansa Musa
             | didn't have a Ferrari F40, or an RTX4090, or air
             | conditioning. He couldn't buy a trip to low earth orbit or
             | get cancer treatment if he needed it. Many people in this
             | day and age are vastly more wealthy than he was.
        
               | Winsaucerer wrote:
               | That's definitely a reasonable way to think about it.
               | Another though is in terms of social status and ability
               | to direct human labor, in which case most people are not
               | more wealthy.
        
               | Retric wrote:
               | On that scale Xi Jinping is likely the richest person to
               | ever live. https://en.wikipedia.org/wiki/Xi_Jinping
               | 
               | You rarely see modern dictators on these lists but
               | populations and economic prosperity have exploded to the
               | point where historic kings can't really compete.
        
               | Winsaucerer wrote:
               | I actually do think of him as a candidate for wealthiest
               | person to have ever lived.
        
               | tonyhart7 wrote:
               | yeah but he is "only" leader, he don't own entire china
               | economy
        
               | rayiner wrote:
               | That one way to measure wealth. Another would be to
               | measure it in terms of how much labor you can get from
               | your fellow humans. Mana Musa was far more wealthy by
               | that measure.
        
               | rcxdude wrote:
               | Indeed, it depends. I think the way this list works it's
               | relative to the available resources at the time, i.e.
               | what percentage of the available wealth did they control?
        
               | throw__away7391 wrote:
               | I visited the Biltmore Estate years ago, the home of the
               | Vanderbilt family. It occurred to me during the tour that
               | all the end result of all this wealth was approximately
               | equivalent to having a 5 bedroom McMansion. A huge
               | percentage of the sprawling property was dedicated to
               | housing servants who performed tasks like laundry,
               | changing the water in the (pre-chlorine) pool, taking
               | care of the horses and carriages of visitors, or
               | preparing meals that today are mostly completely
               | automated or unnecessary. The end result was housing the
               | owners and a few guests in conditions substantially worse
               | than the average modern suburban home.
        
             | aquova wrote:
             | Is there a reason this list wouldn't include any of their
             | successors, who inherited the vast majority, if not all, of
             | their holdings? Did Tiberius not inherit enough of
             | Augustus's wealth to make this top 10 as well?
        
               | anton-c wrote:
               | Iirc he gave some to his wife(?)
               | 
               | Anyone who had multiple people in their will diluted it.
               | Though I feel Augustus got all of Julius' will which goes
               | against this, I imagine powerful people might have a few
               | people they want to leave something for when they die.
        
           | yieldcrv wrote:
           | Mansa Musa was illiquid and could not exchange much wealth
           | for goods and services and had nothing to invest in during a
           | time where the gini coefficient around him would have been
           | 1.0
           | 
           | It is marvelous he found gold and even then he could only
           | give it away freely
        
         | romaaeterna wrote:
         | Document-only claim without any archeological support means
         | that I'm highly skeptical.
        
           | dyauspitr wrote:
           | That's the vast majority of antiquity unfortunately.
        
       | detourdog wrote:
       | What I love about the process is that it seems to have developed
       | by playing with fire.
        
         | JumpCrisscross wrote:
         | > _it seems to have developed by playing with fire_
         | 
         | Or someone melted down a glass and gold object and noticed the
         | gold that floated (precipitated?) out was purer than that which
         | went in.
        
           | defrost wrote:
           | Which is literally playing with fire.
           | 
           | Even today various artists playing with fire rediscover that
           | while gold doesn't naturally work into or onto glass it's
           | still possible to adhere gold to glass if the timings and
           | tempreptures are "just right".
        
         | motorest wrote:
         | > What I love about the process is that it seems to have
         | developed by playing with fire.
         | 
         | Also known as experimentation, which is the whole basis of the
         | scientific process.
        
           | detourdog wrote:
           | What is the difference between the two? No where else did the
           | scientific method develop this process. Play can produce
           | surprising results and methodologies stagnates development.
        
             | motorest wrote:
             | > What is the difference between the two?
             | 
             | There isn't.
             | 
             | Referring to experimentation as "playing with" feels like a
             | attempt to demean the output.
        
               | euroderf wrote:
               | "playing around with" sounds more dignified.
        
               | detourdog wrote:
               | I don't perceive the difference. "working with fire"
               | maybe different but I'm still fine with my word choice.
        
               | detourdog wrote:
               | Sometimes it's best to interpret things in a neutral way.
               | A negative point of view hampers insight. I think the
               | output speaks for itself and doesn't need a defense.
        
               | rdlw wrote:
               | Only if you think there's something wrong with play.
        
         | rsynnott wrote:
         | I mean, you could say that of basically all metallurgy prior to
         | the 19th century.
        
           | detourdog wrote:
           | Ok lets say that.
        
         | cardiffspaceman wrote:
         | Same for Vulcanization.
        
       | kleton wrote:
       | This is called cupellation. Romans used clay crucibles
        
         | declan_roberts wrote:
         | Cupellation is considerably earlier than this method. Some
         | 2,000 years earlier. Cupellation is also very effective at
         | removing base metals.
         | 
         | I'm curious how pure they get gold with this glass method. If
         | it's not as pure as Cupellation then that would explain why it
         | wasn't widely used outside of west Africa.
        
       | bcoates wrote:
       | This article leaves me super unclear on the metallurgical process
       | going on here--you fire gold ore on a bed of glass rubble and the
       | impurities are adsorbed into the ceramic or ???
        
         | colechristensen wrote:
         | Yup.
         | 
         | A whole lot of chemistry process is just _X_ dissolves in _Y_
         | but not in _Z_ , and using that in order to separate and
         | purify.
         | 
         | In this case metal oxides dissolve in glass (sand, which is a
         | silicon oxide, mostly) but gold doesn't A) oxidize under
         | reasonable conditions or B) dissolve in the glass. Sand or
         | glass waste is melted, the _not gold_ dissolves into the molten
         | glass.
        
       | KolibriFly wrote:
       | Innovation doesn't just come from empire-scale institutions
        
       | goodmunky wrote:
       | Africa is a such a vast and diverse region that "Africans" is
       | nearly meaningless in this context. But you already know that.
        
       | snthd wrote:
       | Can this displace the mercury process used by illegal miners?
       | 
       |  _Reuters - Insight: Amazon rainforest gold mining is poisoning
       | scores of threatened species_
       | https://www.reuters.com/business/environment/amazon-rainfore...
        
         | latchkey wrote:
         | Cyanide usage is pretty bad too.
        
       | AlecSchueler wrote:
       | They had it in medieval Mali but it seems inaccurate to say
       | "Africans" had it even though it might technically be true.
        
       | ChuckMcM wrote:
       | Anyone have a link to the paper?
        
       | dondakirme wrote:
       | interesting
        
       | bargle0 wrote:
       | How impure was the gold dust from the chemical supply company?
        
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