Ocubra

Not all errors are useless, this one lead us to a productive way of extracting iron. Watch it, learn this error, and you'll be a great ironsmith, apprentice. And remember, errors are good, they teach you, learn from them.

— Ironsmith master to an apprentice.

Ocubra is one of the old method of extracting iron from an iron vein created by the Kreanes. This method is lost in time, with parts of it remaining in Ubral's mountains. It is now used other methods to extract iron and thus it is not a great lost.
This technique made the Kreanes famous blacksmiths.

Discovery

Discovered by the kreanes, almost a millenia ago.
It was discovered while kreanes where experimenting with a new way to forge and to extract copper. When they tried to extract the copper, they also extracted all the iron possible that was mixed in that copper vein.

Histoy

Kreanes created this technology a millenia ago by accident while trying to extract copper. After discovening that, they tried improve it and made it only to work with iron, which was an extremely valuable and rare metal a millenia ago.
They recorded this information in a vegetable paper and they transpased the information to newer vegetable paper each decade (as the vegetable paper has a lifespan of 15 years), but when Ubral was destroyed, the survivors forgot about these papers and they ended up decaying, taking the valuable informations with them.

Prompt 26: Write about a technology from the history of your world - is it lost to the ages, or did it shape the world today?

Access & Availability

Now it is lost in time, no one remembers how it worked and there seems to be no records of how to do it as Kreanes used a vegetable paper during that times, and that paper has a lifespan of at most 15 years.

Complexity

Complexity is nowadays unknown but it is supposed to be the most complex tecnique used in the last millenia.

Ubral's ironsmith

The ironsmiths of Ubral were famous in their time, for their excellent smith-work with iron, for they only worked with iron since the discovery of this technique. They soon got the ironsmith title attached to them, as a second name, even if that person did not work as a smith. And sooner, all Kreanes started to be called ironsmith, even when they were not from Ubral nor were smiths.