Periodic Table and Currency
Last week, Dr. Kiyanda (my roommate at ENCS Concordia University) and me, we were talking about metals as currency materials. After checking couple of websites, as some people mentioned it before on TV, we noticed that there are only three metals on the periodic table (Gold, Silver and Copper) which are eligible for processing and making metal currency.
Our criteria about the metal currency was, it (1) could be processed by middle age technologies, (2) not so rare and not so common in nature, (3) doesn't oxidized suddenly like Aluminum. Except these three, some metals could be find commonly in nature like Iron or so rare like Platinum, some others absolutely have been dangerous to touch or carry like Zinc, some of them were impossible to extract and process in those days like Titanium.
After checking some properties of possible metals, we could understand the metal currency idea. It was a nice morning conversation.