This Guardian article talks about how uranium was mined at the beginning of the 1500s. The Guardian is a pretty reputable newspaper as far as I’m aware, so I am willing to believe them. Out of curiosity, I attempted to find out why anyone would mine uranium in the 1500s. A quick google tells me it was only defined as an element by Martin Klaproth in 1789, and the article mentions that uranium’s radioactivity wasn’t discovered until around 1896.

The Wikipedia page mentions ceramic glazing, but also mentions it has been mined since the Roman empire, so I'm not sure what to believe there.

So what did people think they were mining before this? Was it just some kind of heavy stuff? Was there any link between the chemical and people falling ill? Or was it just in such small quantities or handled so little that no one noticed?

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    Please cite the "infamous Wikipedia" page is it WIkipedia:Uranium If so, the answer seems to be in the difference between "isolated" and "discovered"
    – MCW
    Dec 19, 2022 at 15:22
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    Limestone was "mined" by ancient Egyptians. Calcium was "discovered" in the 1800s. Same pattern for silicon in the stone age tools or aluminum in the clay pottery.
    – nasu
    Dec 19, 2022 at 21:39
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    The guardian is famously weak on technical, scientific details. In this case it fails to distinguish between mining "uranium" and a mineral that contains uranium. Many elements were not isolated or recognised until the 20th century with only a few being recognised as early as the 18th century (including uranium).
    – matt_black
    Dec 20, 2022 at 10:28
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    @MichaelHarvey It is more commonly referred to as the Grauniad due to the common typos by its subeditors.
    – matt_black
    Dec 21, 2022 at 15:29

1 Answer 1


Uranium oxide in the form of the mineral pitchblende was known and mined - as the Wikipedia article says. So the short answer is that as far as anyone in the 1500s was concerned, they were mining pitchblende and using it to make things turn yellow - they had no reason to care about where pitchblende came from.

The use of uranium in its natural oxide form dates back to at least the year 79 CE, when it was used in the Roman Empire to add a yellow color to ceramic glazes. ... Starting in the late Middle Ages, pitchblende was extracted from the Habsburg silver mines in Joachimsthal, Bohemia (now Jáchymov in the Czech Republic), and was used as a coloring agent in the local glassmaking industry. [WP]

Discovering what pitchblende itself was composed of did not come until Klaproth (or possibly, per Wikipedia, until Péligot in 1841 - Klaproth thought he had identified it, but Péligot was the first to extract pure uranium).

This situation was not unique to uranium; cobalt ores have been used for millennia to colour things, but the underlying element was not identified until the mid-18th century.

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    We are mostly water and drink it all the time, but hydrogen was only recognized as such in 1766.
    – Spencer
    Dec 19, 2022 at 18:58
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    @Spencer - Philosophical question: does that make a well a "hydrogen mine"?
    – T.E.D.
    Dec 19, 2022 at 19:03
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    @T.E.D. Only if you intend to extract the hydrogen, and that's why it's an anachronism to claim that anyone "mined uranium" in the 16th century.
    – Brian Z
    Dec 19, 2022 at 20:20
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    Fun fact about those silver mines in Joachimsthal - coins produced there were called "Joachimsthalers", later shortened to "thalers"; this is where the English word "dollar" comes from.
    – Skyler
    Dec 20, 2022 at 14:32
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    @T.E.D. No, since liquid mines are called wells, even when they're oil or natural gas and not water. But if you had an ice cave...
    – Bobson
    Dec 21, 2022 at 3:54

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