Why You Won't Find Gold Coins (Ever) in Bulk Lots of Uncleaned Ancient Coins
Bulk uncleaned coins
Virtually all uncleaned Roman, Greek, Byzantine, Medieval and specialized uncleaned coins sold bulk lots for the retail market (or even in private transactions between excavators wholesalers) are found in roughly the same fashion. The end buyer purchases between 10 and 1,000 coins at a time, with the mean purchase between 25 and 100. The retailer either sells the coins in fixed prices for unites ranging from 1 coin to 1,000 at a time, or auctions them, usually on the same one or two days each week. Many of the most popular European vendor auction about 500 - 2,000 coins a week, while American vendor tend to auction smaller numbers (a few dozen to a couple hundred) and rely much more heavily on fixed-price (or "best offer") retail sales.
One or, more commonly, a few, excavators armed with metal detectors, picks, shovels and similar paraphernalia systematically trek across the local countryside near the towns where they reside. Some are professionals who work 9-5 at it, so to speak. Additionally, great armies of amateur "detectorists" comb the fields as hobbyists and weekend hunters. A very different set work in agriculture. Each spring there is a surge in the availability of wholesale Roman coins (likewise, other artifacts of all kinds from the Stone Age to WWII) as farmers clear fields and disturb soil.
Many "detectorists" pick up their objects (coins included) a few at a time, here and there. What they are really hoping for is the score of a lifetime—a buried hoard of thousands of coins, be they bronze, silver, or gold, as pictured below. Any region or town will have at least one person known to buy these finds and potentially capable of accumulating tremendous numbers of valuables from 19th century military buttons to stone arrowheads. The more dedicated, professional hunters, alone or in teams, are able to strike out on their own and make a fair living it, depending on where they live, their equipment, and general skill. Archaeologists spend years carefully surveying and sampling the soil and its contents, treating such sites as tremendous stores of knowledge to be dug out with great care and painstaking data collection. Workers excavating such a site for wholesale and eventual retail markets can clear a pit of such size within a few weeks and perhaps make a season's or even a years wages. Some nations have what are called "Treasure Laws" in which individuals may keep all or a portion of coins found, once professional archaeologists work the sites.
These are points of tremendously heated controversy with scholarly archaeologists. See, for instance, the blog of British archaeologist, Paul Barford, an advocate against what he views as the "looting" of coins and other antiquities. He is opposed at least equally vehemently by many in the antiquities/coin business, who have given him the utmost in scholarly flattery by creating numerous blogs specifically devoted to mocking him and, at least twice, co-opting his own name to create such websites. Indeed, any signs of sympathy, or lack of sufficient disrespect, from a coin collector/dealer (such as here) risks incurring the ire of those who view him as a serious threat requiring persistent condemnation.
Eastern Europe is the most fertile ground for finding ancient Roman coins which supply the vast bulk of retail uncleaned coins found on eBay and specialized websites dealing in ancient coins. Some estimate about one million per year on eBay alone -- the primary market engine for these transactions (this figure seems not to be too far off based on my counts of items sold on the US eBay site by the major vendors; and it may well be a major underestimate).
In some large samples (e.g., 14,000 coins dug up at the Athenian marketplace) about 1% of coins were silver, considerably more than one finds in uncleaned coins at the retail level. However, there is reason to think that an even higher proportion of coins struck were silver or gold, since bronze coins were more likely to be lost, one way or another, or forgotten in smaller hoards than were silver and gold coins, often kept in large quantity by government bodies. On the other hand, gold and silver coins were continually melted down by new governments and rulers to produce coins of their own.
It is difficult to estimate how many gold coins were struck in antiquity, much less how many ancient gold coins persist today. In one minting alone, the Athenians struck 84,000 gold staters weighing 8.5g each to pay mercernaries. (The Romans and Byzantines certainly struck and collected massively more gold coinage regularly; indeed, there was trade in gold stretching from India to the Middle East to Nubia to Spain and England.) Thousands of ancient Roman, Greek, and Byzantine gold coins enter the auction and retail market in Europe, Asia, and the USA every month. Numerous museums and other organizations have collections of ancient gold coins numbering in the thousands. Thus, although rare, it seems reasonable to assume a great many are still out there to be found.
Many wonderful, rare, and valuable coins are surely to be found in uncleaned coin batches for sale on the open market. Sometimes one does find a silver coin or two in a batch of, say, a couple hundred or 1,000 especially encrusted uncleaned coins.
Of approximately 200,000 Roman coins recorded by the UK's Portable Antiquities Scheme (finds.uk), designed to gather data from public and private finds, only 143 are recorded as being made of gold. That seems very few, but if one buys a couple of thousand uncleaned coins, and they are randomly distributed, shouldn’t it be possible to find one gold coin in a batch or two of 1,000 uncleaned coins?
Shouldn’t it be possible to find one gold coin in a batch of uncleaned coins, then, at least once in a while?
To the dismay of many new collectors, and contrary to the claims of many uncleaned coin sellers, gold (or electrum) Roman, Greek, and Byzantine coins are virtually never found in uncleaned lots. Occasionally buyers report finding small, light weight Indian gold coins of little value mixed into the lots, so as to stir up buzz about a seller's gold content in their coins. But an actual Roman or Greek gold coin is virtually never found. There is a simple reason why.
Unlike cuprous (bronze, copper, brass) coins) that have been exposed to the elements (even oxygen alone) for hundreds of years or more, gold coins do not change color, accumulate a patina (oxygenation), or collect detritus in considerable amounts. They come out of the ground, thousands of years after they went in, looking just the same.
The Roman and Byzantine gold coins pictured below have been exposed
to the surface of the earth for the first time in more than 1,000 years. Notice
that, even for those still mostly encased in earthen surroundings, the gold is
very clear. The bonds between coin and earth consist almost entirely of
friction and gravity, very much unlike the bond between bronze coins and
earthen materials. The dirt can be rinsed off easily with water or mechanically
removed with a wet cloth in very short time.
Contrast these with bronze coins. Below you see a
pile of Greek Imperial Judaean coins that were buried in the soil for just over
2000 years. Typical of any "AE or Æ" coin (with cuprous), including
but not limited to copper, brass (copper alloyed with zinc), bronze (copper
with tin), they have a rough green layer of oxidation at the surface. This is
often found on silver coins as well, especially those with high content of
"base" (cheaper) metal. This is what usually must be
"cleaned" from "uncleaned" coins and conceals whether they
are worth a lot or a little.
The photograph below is particularly informative as it shows base metal coins, mostly likely including bronze, copper, and brass coins (possibly including silver), being unearthed alongside gold coins. Note that the gold coins are untouched by time and the conditions in which they lay for 2000 years, while the other coins are discolored, encrusted, and likely fused together by oxidation.
In any profit-generating dig site, those working the
dig will immediately remove the obviously gold coins (worth several hundred
time more than the others) to sell individually. If some of the silver coins
retain their appearance as being made of precious metal, they will be next to
to be pulled from the rest of the hoard.
Oftentimes one finds coins that show a bit of
original ancient surface silvering, or that are the same size and shape as
ancient Roman and Greek silver denominations (coins that are denarius or
Antoninianus shaped; or for suspected Greek coins, ones shaped like a Stater,
Drachm, Shekel, Tetradrachm, or the like), have modern test cuts/scratches on
the surface, made with a sharp metal instrument, to determine if the coin is
silver "all the way through" or just appears so at the surface. If
found to be solid silver, they are also removed from the bulk of coins that aare
sold to consumers in groups of "uncleaned coins.”