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From time to time, I see articles implying the medieval use of chromium, however sparingly, in forging weapons (near east or central Asia) Eg. https://www.scie

From time to time, I see articles implying the medieval use of chromium, however sparingly, in forging weapons (near east or central Asia) Eg. https://www.sciencedirect.com/science/article/abs/pii/S030544032030145X https://www.sciencedirect.com/science/article/abs/pii/S03054...

adrian_b 1y ago
Those who made such early examples of chromium-containing steel had no idea that chromium existed. What happened is that they have found a place with chromite and they have believed that they have found magnetite, because both are heavy blackish stones. Most likely the chromite was actually mixed with true magnetite, which is always much more abundant (chromite is a mixed iron-chromium oxide, while magnetite, which has an identical crystal structure, is a mixed Fe(II)/Fe(III) oxide). Then they have used the magnetite mixed with chromite exactly like they knew to use magnetite, for making steel. The steel happened to be better than what they had made before, and they were happy that they had found a source of particularly good magnetite for making steel. After gathering experience, they have probably adjusted their techniques for smelting and forging to work better with steel made with the natural magnetite-chromite mixture, but that is all the extent of their knowledge. Because the ancient smiths did not know how to do chemical analyses, they had no idea why using similarly looking minerals mined from different places results in metals with different properties. In the ancient world it was well known that certain steels or bronzes made in certain places are much better than the steels or bronzes made in other places, so the price of steel or bronze varied a lot based on its provenience. These quality differences were frequently caused by impurities in the source minerals used for metal production, whose presence was unknown for the ancients, but they were aware of the qualities of the metals produced there. No knowledge whatsoever about the existence of chromium has existed anywhere, before the creation of the modern chemistry, based on the concept of chemical element, slightly before the French Revolution, towards the end of the 18th century, which triggered an intense search for the discovery of new chemical elements.
- gsf_emergency_2 1y ago
  What you say sounds reasonable, but the university PR claimed that they knew chromite was special >Crucially, analyses using Scanning Electron Microscopy enabled them to identify remains of the ore mineral chromite [rusakhtaj], which was described in Biruni’s manuscript as an essential additive to the process. https://www.ucl.ac.uk/news/2020/sep/chromium-steel-was-first-made-ancient-persia https://www.ucl.ac.uk/news/2020/sep/chromium-steel-was-first... This still doesn't say they knew about chromium ofc just that it was not just magnetite. Ofc one has to read farsi to make sure rusakhtaj wasn't a common alias for magnetite. Who knows, rudimentary awareness of the concept of "alloy" might have existed there..
  - adrian_b 1y ago
    The original text would have to be read extremely carefully to conclude that they knew that chromite is really different from magnetite. I have read many ancient texts about metallurgy and the like, where they were using a bewildering amount of various names to designate the various kinds of ores and of produced metals. Despite that, they did not think that there was any essential difference between the many kinds of magnetite or of chalkopyrite and so on. They were habituated with the fact that the natural minerals extracted from different places have never exactly the same properties. Now we know that this is caused by slightly different chemical compositions, but they just knew that some are better for a certain purpose, while others are worse, without knowing why this is so. Because this is how all the minerals they knew had always behaved, it was not considered a surprising fact. It was just accepted that you have to know the exact origin of a mineral, to assess its value and its suitability for a desired purpose. So I doubt that they had considered chromite as a stone distinct from magnetite, like they considered e.g. magnetite distinct from pyrite, where the appearance of the stones is easily distinguishable. Even if they had thought that chromite is not a better kind of magnetite, but something really different, they still would have not imagined that chromite contains another metal that becomes alloyed with iron, like they knew to alloy tin with copper or the like. They would have thought that adding chromite stones to the minerals for iron extraction improves the resulting steel for some unknown reason.

adrian_b 1y ago

Those who made such early examples of chromium-containing steel had no idea that chromium existed. What happened is that they have found a place with chromite and they have believed that they have found magnetite, because both are heavy blackish stones. Most likely the chromite was actually mixed with true magnetite, which is always much more abundant (chromite is a mixed iron-chromium oxide, while magnetite, which has an identical crystal structure, is a mixed Fe(II)/Fe(III) oxide). Then they have used the magnetite mixed with chromite exactly like they knew to use magnetite, for making steel. The steel happened to be better than what they had made before, and they were happy that they had found a source of particularly good magnetite for making steel. After gathering experience, they have probably adjusted their techniques for smelting and forging to work better with steel made with the natural magnetite-chromite mixture, but that is all the extent of their knowledge. Because the ancient smiths did not know how to do chemical analyses, they had no idea why using similarly looking minerals mined from different places results in metals with different properties. In the ancient world it was well known that certain steels or bronzes made in certain places are much better than the steels or bronzes made in other places, so the price of steel or bronze varied a lot based on its provenience. These quality differences were frequently caused by impurities in the source minerals used for metal production, whose presence was unknown for the ancients, but they were aware of the qualities of the metals produced there. No knowledge whatsoever about the existence of chromium has existed anywhere, before the creation of the modern chemistry, based on the concept of chemical element, slightly before the French Revolution, towards the end of the 18th century, which triggered an intense search for the discovery of new chemical elements.

gsf_emergency_2 1y ago
What you say sounds reasonable, but the university PR claimed that they knew chromite was special >Crucially, analyses using Scanning Electron Microscopy enabled them to identify remains of the ore mineral chromite [rusakhtaj], which was described in Biruni’s manuscript as an essential additive to the process. https://www.ucl.ac.uk/news/2020/sep/chromium-steel-was-first-made-ancient-persia https://www.ucl.ac.uk/news/2020/sep/chromium-steel-was-first... This still doesn't say they knew about chromium ofc just that it was not just magnetite. Ofc one has to read farsi to make sure rusakhtaj wasn't a common alias for magnetite. Who knows, rudimentary awareness of the concept of "alloy" might have existed there..
- adrian_b 1y ago
  The original text would have to be read extremely carefully to conclude that they knew that chromite is really different from magnetite. I have read many ancient texts about metallurgy and the like, where they were using a bewildering amount of various names to designate the various kinds of ores and of produced metals. Despite that, they did not think that there was any essential difference between the many kinds of magnetite or of chalkopyrite and so on. They were habituated with the fact that the natural minerals extracted from different places have never exactly the same properties. Now we know that this is caused by slightly different chemical compositions, but they just knew that some are better for a certain purpose, while others are worse, without knowing why this is so. Because this is how all the minerals they knew had always behaved, it was not considered a surprising fact. It was just accepted that you have to know the exact origin of a mineral, to assess its value and its suitability for a desired purpose. So I doubt that they had considered chromite as a stone distinct from magnetite, like they considered e.g. magnetite distinct from pyrite, where the appearance of the stones is easily distinguishable. Even if they had thought that chromite is not a better kind of magnetite, but something really different, they still would have not imagined that chromite contains another metal that becomes alloyed with iron, like they knew to alloy tin with copper or the like. They would have thought that adding chromite stones to the minerals for iron extraction improves the resulting steel for some unknown reason.