Gundestrup cauldron

>>8303715
Aliens confirmed

>>8303715
They didn't make it, a more skilled civilisation made it for them.

they could have just found some crystalline silver

Or one guy was mad good at cooking off slag and just didn't write a 10 Things You NEED To Know About Smelting Silver Before Christ Arrives click bait article

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>>8303720
more like alchemy

>>8303738
>Or one guy was mad good
this. artisans often took trade secrets to their grave.

>>8303715
"Precious" metals tend to be less reactive than more common metals, which makes them easier to smelt.

Also, at that time silver ore probably wouldn't have been recognised as such unless the silver content was particularly high, possibly even with a high proportion of elemental silver.

>>8303715
Suppose the Celts lacked the the ability to detect silver ore, to mine that ore, and to smelt it. They could have just taken some Roman silver coins and used that to make the bowl. I'm pretty sure the romans were in Britain before 1 AD and even if the Romans weren't boats existed, as did trade and the practice of hiring mercenaries. All the Celts had to be able to do is take silver of one shape and make it another shape.

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>>8305475
would the Romans have been able to make Silver that pure?

>>8305512
>>8303715
97% isn't all that pure. Most silver at that time was found in lead ore, and needed to be separated chemically. Purification of precious metals was developed to a fairly high degree in the ancient world, as a result of the need for consistent purity in coins, and the desire to recover pure precious metals from debased alloys.

The abundance of lead in the Roman Empire was a result of lead being a byproduct of silver mining. The amount of lead mined wasn't equalled again until the industrial revolution. Silver can be separated from lead by "cupellation", or heating to a high temperature in an oxidizing environment, which causes the lead to oxidize, and the oxide to separate from the silver. By carefully controlling the temperature, the lead oxide can be melted while the silver is kept solid so they are easily separated (generally, the lead oxide is allowed to soak into the porous material of the cup). This also has the effect of converting any silver oxide to silver, and works in general to separate precious metals from base ones. This was done for thousands of years before the rise of Rome.

Silver ore can occur with little gold content, so fairly pure silver can be had this way.

Parting of silver from gold was figured out much later, only around 500-600 BC (still hundreds of years before this cauldron). It's not a particularly elaborate process either: roasting gold/silver foil with table salt and a few other ingredients in a sealed pot (they were working by trial and error, so only simple methods were discovered). The silver is made into silver chloride and boiled off (to condense elsewhere), while the gold resists reacting and has a much higher boiling point than silver chloride. The silver chloride separates to produce silver metal on exposure to light.

Reasonable purities can be reached with these simple methods, though nothing like modern "five nines" purity accomplished with scientific understanding of chemistry and physics.

>>8303715
I'm not sure, so it's probably aliens

>>8303738
>10 Things You NEED To Know About Smelting Silver Before Christ Arrives
underrated post

>>8306287
A few more points:
This property of silver salts disassociating on exposure to light is the basis of photography. The effect of darkening in the light is fairly obvious, and the "camera obscura" method of focusing light on a screen in a dark room was known since ancient times, but nobody put them together until about 1800. Silver nitrate was used in the first experiments, but silver chloride was also important from early on:
https://en.wikipedia.org/wiki/Calotype

Further improvements were made by the alchemists of the medieval period, as they fumbled toward what later became chemistry with a particular emphasis on extracting purer gold and getting more of it from poorer sources. Over the centuries, they learned to use sulphate salts rather than chlorides, and then developed acid parting, culminating in the development of aqua regia, which can even chemically transform gold into a liquid (chloroauric acid) for purification using convenient benchtop wet chemistry.