You should be aware that the first coins to show up in the world was around 600 B.C of which has a connection with Greece. These coins were unique as they were made of electrum that comprises an alloy of gold and silver. Before that, there are other currencies that were used since coins were not known at all. Since then, more unique and beautiful coins have been produced in the world and people are using them.
But it is fundamental to note that old coins are more valuable since they have historical significance and other factors. It is paramount to note that foreign coins are still valuable and it is crucial that you be well grounded on that. As you analyze the value of these coins you will need to focus on demand, provenance, design, mintage, population estimates, age, errors, and many more.
You need to analyze and identify these coins when you are determining their value and that will help you a lot. This is easily done through online research or seek help from numismatic experts. In case you have an interest in challenge coins ensure that you know the difference that exists between soft enamel vs hard enamel coin.
There is Edward III Florin in England. Edward III had an attempt of introducing gold coin that was used in Europe and England and its value was six shillings. This attempt was unsuccessful and was withdrawn from the market since it was considered to be underweight. However, these coins are no longer there but the only remain coin is preserved at the British Museum.
There is also Ummayad Dinar from the Middle East. These coins are valuable as per their demand since they were auctioned at 3,720,000. There is a short line with text that makes this coin have the highest value and is significant within the Islamic faith.
Also, know Servilius Caepio Brutus AV Aureus (Ancient Roman). It is paramount o be aware that there are over 80 of these silver coins that are there, but only three are only three gold coins. One of these gold coins is preserved in the British Museum, the send one in Deutsche Bank while the last one was auctioned for 2.7 million.
The other type of coin that is valuable is a single 9 pond from South Africa. This coin is the rarest and this has made it to be known as the king of South African coins. This coin also is amongst the five expensive coins in the world of which in the year 2010 valued about $4 million.