Have you ever pondered over the possibility of that old ring being made of gold, or the amount of silver in a piece of jewelry or flatware? We all have from time to time. In many cases a visual examination tells almost nothing about what may be on the inside of any object. This is especially true of coins, which can be particularly deceptive because they are not marked in any way to show the nature of the metal.
Jewelry and tableware is usually marked in some way to show the exact fineness of its makeup if it is gold or silver. A gold locket, for example, may be stamped 12K if it is made of 50% gold. Pure gold is designated as 24 Karat. If a piece of jewelry is made of some other metal and gold plated, it can not be marked in Karat weight, but may be stamped in some way to indicate that it is gold plated, gold finished or gold overlay.
Silver objects are often marked “Sterling” or “Coin” to show the fineness of the silver. All silver is rated on the basis of 1,000 parts of pure silver. Sterling silver is .925 fine, meaning that it is 92.5% pure silver. “Coin” silver is .900 fine, or 90% pure silver. This does not mean that all coins are .900 fine. Many of them are not. It is just a term that was often used to stamp silverware before around 1850. All pre-1965 United States silver coins were made to the .900 fine standard.
But coins are not usually marked with their fineness or gold content, so how is one to know what’s really on the inside of a coin, or a piece of unmarked jewelry. There is a way. It is used frequently in detecting counterfeit coins, and to determine the value of silver and gold bullion. It’s quite a simple test that anyone can do at home with some inexpensive equipment.
The procedure is called Specific Gravity testing. It is a measurement of the density of a mass, and is based on the principal, which states that alloys of different pure metals displace varying amounts of water, depending on the density of the metal and the proportion of each metal used in the alloy. Specific gravity of the mass is determined by measuring the volume of water displaced by the object being tested.
The concept of specific gravity dates back to ancient times in Greece, and has changed but little during the ensuing centuries. It is the oldest and still one of the best methods for quickly and accurately determining the probable composition of an alloy.
Chances are that you will not have at home the special SG charts, scales and other paraphernalia needed for performing an accurate specific gravity test. That should not deter you if you have need for such testing. You probably can persuade someone to help. A chemist, pharmacist or school lab usually can do the job easily.
The most common procedure used today is to weigh the coin or questionable object in air to first get a “dry” weight. Then the object is weighed in water. The “wet” weight is then subtracted from the “dry” weight, and the balance is divided into the “dry” weight. The resulting number is the Specific Gravity of the object. You must then refer to a standard SG chart to determine the nature of the metal that was tested.
Various metals will test differently. Coin silver, which is .900 fine, has a specific gravity of 10.34. Gold, which is much denser, has a specific gravity of 17.16. The U.S. clad coins which are made of 40% silver have a SG of 9.53. Copper coins and other items made of copper have an SG in the range of 8.82 to 8.92.
The Most Common Coin In The World
Over the centuries billions and billions of coins have been made for countries ranging from Afghanistan to Zambia. They have been made and used from 650 B.C. to the present, and continue to be made in ever increasing numbers. When you consider that none of them are ever intentionally thrown away, and that they all have some value to someone, it’s a wonder that we are not inundated with old coins. That would be a pleasant situation if there was so much old money that there was more than enough for everyone, but alas, that is not to be. When money gets old and useless, it is usually called in and melted for re-coinage.
Looking back in history we find that some kinds of coins were so popular that they were made for decades without any change in the design, size or weight. You might think that such longevity would become boring for the people who used those coins but evidently there were no complaints. Several coins have even managed to continue on without change or interruption for hundreds of years. Searching for the one with the longest life span proved to be quite a challenge and presented a number of contenders. What I set out to learn was which coin was minted in the greatest numbers throughout its span of issue. In other words, “what is the most common coin in the world?”
449-404 BC Ancient Silver Tetradrachm
One prime contender has to be the ancient silver tetradrachm coin of Athens. The first issue of these coins was made in or around the year 560 B.C. The front side of this coin shows a head of the goddess Athena wearing a helmet. On the reverse is a standing owl and the abbreviation AqE that stands for Athens. Coins of this design were made for the next 475 years up until around 85 B.C. The only variation was a slight modification of the design made around 200 B.C. The redesigned pieces are still called “new style” coins.
The Athenian coins were simply so well made and trusted by everyone that there was no need to change them in any way. Over the centuries tens of thousands of these popular coins were lost or destroyed and today they are no longer common by any standard. When they were in daily use, and being spent by such men as Plato and Aristotle, they must have been extremely common.
Maria Theresa Thaler
A similar long-lived trade coin of more recent vintage is the Maria Theresa silver thaler of Austria. That coin was first issued in 1780 when the queen was still on the throne. It proved to be an extremely popular coin because it was the size of a silver dollar and contained a full three-quarters of an ounce of pure silver. After the queen died there was a continued demand for more of the thaler coins, and the Austrian Mint went on making them for over 100 years. Then several other world mints began producing more of the coins for their own purposes. Today, more than two hundred years later the Austrian Mint is still producing silver Maria Theresa thalers with the 1780 date and design, making this one of the longest surviving issues of modern times.
2010 Lincoln Cent Redesign
Another hot contender for the title of “most common coin in the world” would be our own United States Lincoln cent. The reason this is a distinct possibility is that billions of pennies are made each year, and they have been made since the coin was introduced in 1909. The front of the Lincoln cent has not changed in all that time, but a different back has been used since 1959 when a change was made to mark the 50th anniversary of the coin. As the penny survived through 2009 it celebrated one hundred years of issue and the longest lasting American coin by far. It may also establish a world’s record for the number of coins made during its lifetime.
Old Chinese coin made during the reign of Kangxi Emperor (1654–1722) in Qing Dynasty
As of now it seems that the uncontested winner in the most common coin contest has to be the copper one-cash coin of China. Those coins are about the size of a U.S. quarter and have a square hole in the center. The hole was put there so that these low-value coins could be strung together in units of 1,000 pieces. They were the standard money of China for over two thousand years, and in all that time each coin was nearly the same size and design. The first of the cash pieces was made around 200 B.C. and the last in 1912. There is no way of telling how many billion of these coins were made over the 2,112 years of their existence, but judging by the millions that still survive today, they surely hold the all-time record.