Coins are used along with currency notes to exchange goods in this world. Lets learn how coins are made. History of Coins: Coins were first made and used by Libyans in 640 B.C. About 40 years from there on, the concept or the idea of coins spread to ancient Greece. Greece people engraved photo of their Goddess Athena on coins. Around 500 B.C., chinese made their mark in producing coins for which they used cheap metal copper instead of Gold and Silver. In fact, today also, China makes their coins of copper, nickel and other cheap materials. When coins are made, there can be leftover which is usually, silver. This leftover is again used for producing coins. It is then put into burning furnace with the temperature of 2100 degrees farenheit. Then bar like shape is given to melted silver. The height of this bar is ideally one and a half inches high and 5 inches wide. Then this long bar is cut into individual bars. These individual bars are around 30 inches long. These individual bars are then moved into a machine where 9 tons of force is applied to make bars thin and flat. Flattened bars are then again pressed so that exact height of the bar is produced as per the denominations set. Then this flattened bars are then moved into stamping machines where machines have size of coins and are stamped on the bars and circular shaped flat coins are separated out from the bar. The leftovers , as discussed above , will again be used at the time of producing coins in next cycle. Good example of recycling. These flat coins are then collected and moved into tub where cleaning solutions along with water is spread over these coins for cleaning process. This process continues for 20 minutes and then the leftovers are separated out from the coins. These coins are then cleaned with special cloth which will ensure that there is no water left on coins. These coins are again moved into heating furnace where these are not heated completely but upper visible part of coin is warmed so that engraving of photo and art can be made easily on the coins. Usually, photo and art work , combined together, are used for engraving on the coins. Selection of photo and art work is decided using computer where art is designed based on collage of different art made. This is also applicable for photos. Then best featuring combination of photo and art are used to stamp on the  coins.Before directly stamping of designs are done on coins, plaster is taken which is of size 3.5 diameter and design is made on this plaster. With the help of engraving machine and computer guiding the engraving machine, design is made on the plaster. This design on plaster is usually in 3 dimensional with rough details. Once engraving of design is done on plaster, negative can be prepared in which design is present by keeping negative on the plaster. Then designers then use this negatives to enhance the design on plaster and this is done by hand. Once the whole design is complete, positive mould of the design is done. Positive mould is generally casted into rubber. Then this rubber mould is used with special machine which recasts the design into brass with 1/3 rd of the size as  compared to that of rubber mould. This process takes 36 hours. Then using microscope, country of issue and other details which are generally very minute in display are then stamped by the designer. Once this is done, again reduction process is applied on this brass mould which again takes 36 hours and then reduces the size to one and a half times to that of brass mould size. This size eventually becomes the actual size of the coin. The flat coins which were made in earlier process are then kept above the negative prepared in second reduction process. And using coin stamping machine, coins are made and the designs are then engraved on flat coins. This is done using one coin at a time. Typically, several 100 coins are made every minute. This is how coins are made and are used for exchanging goods.