Ancient coin collecting is another world away from collecting modern world or US coins.

To the uninitiated, ancient coin collecting may look like a great mix of unrelated small states, followed by the all-encompassing Roman Empire, each with a different coinage system. It may appear to be difficult to focus on a specific field to collect.

People collecting coins of the United States (as an example) typically choose a specific denomination. Looking at the world of the many Greek city-states, this may not seem possible. Many people looking for an area to collect within the Roman Republic (or later Roman Empire) may simply find collecting a portrait coin, which represents each emperor or member of his family on a coin, may be the answer.

US collectors will acknowledge that the greatest interest in US coins is in the coins struck in series in large diameter. This includes half dollars, silver dollars, $10 gold eagles and $20 double eagles. In ancient Roman coins, the largest denomination was not necessarily one of the most valuable denominations regarding their value today. It is the bronze or orichalcum composition sestertius.

The silver denarius, a coin about double the size and weight of a silver dime, was the mainstay of the Roman economy. A trained artisan typically made a denarius a day as his wage. The coin had some good purchasing power.

Above the denarius was the gold aureus (later solidus) and occasionally some of its fractions. Below the denarius was the occasional fractional silver coin, then the sestertius valued at four to the denarius, then lower bronze composition coins, including in descending order the dupondius, as and quadrans.

While the denarius was about the diameter of the dime, the sestertius was closer to the half dollar in diameter. The sestertius was made of either a brass composition mix called orichalcum or of bronze. Although no one alive today ever saw a freshly minted sestertius, the coin probably looked bright and gold-like when new because of the brass in it.

Collectors of ancient Roman coins often seek out the gold aureus or the silver denarius, but the most challenging and probably most ascetically appealing denomination because of its size is the sestertius.

Considering that the sestertius was commonly used in circulation, finding high grade specimens can be an expensive and elusive challenge. The metal composition doesn't help, since such metals react with whatever they encounter while in the ground.

Most ancient coins in collections today were buried at some time in their history.

Sestertii come with many different patinas and finishes, since they have typically been buried. The more eye appealing the patina, the better the coin may be valued today.

An emerald green patina is significantly more desirable than what is generally called a Tiber patina, a golden bronze color suggesting the coin might have been cleaned. In other words, the surface eye appeal of the coin mirrors the same standards usually accepted by half and large cent collectors.

Interestingly enough, the grading of sestertii also mirrors those of half and large cents. A sestertius in Very Fine condition is still very attractive with minor rub on the high points. By the time the coin is graded Extremely Fine or better, you are dealing with an extremely desirable specimen. Add the right eye appeal from patina and you could be looking at a very expensive specimen.

Sestertii are typically collected for the portraits on the obverse. Most collectors try to collect an art gallery of the emperors and their families. A few people collect for reverse themes such as Judaea Capta coins marking the defeat of the Jews in the First Revolt.

One of the "Cadillacs" of collecting is a set of sestertii of the 12 Caesars, the first 12 rulers of Rome between Julius Caesar and Domitian. These 12 simple coins may take a lifetime to assemble. Few people ever succeed.

A portrait sestertii of Tiberius might be encountered once every several years in collector markets. There are no sestertii of Otho. You have to be satisfied with the early modern fantasy Paduan issue or a very rare medium bronze coin of Antioch.

Vitellius is very rare and incredibly expensive when encountered in virtually any condition. This is not for the faint of heart. It doesn't seem to matter if you have the money. It is the availability which is the challenge.

In terms of attractiveness and history you can't beat this series. It's a great challenge and fun to collect.

Bob Reis has been a collector for forty years, a dealer for twenty, and a writer on numismatic subjects for ten. You can reach him at POB 26303, Raleigh NC 27611 USA, or by phone at(919)787-0881 (8:30AM - 10:00 PM EST) or fax at(919)787-1882.