hotwheelsearl Posted June 4 · Member Share Posted June 4 I am not trying to call anybody out, but I have noticed an odd trend where some collectors of what I could consider the more "advanced" variety tend never to list the diameter of their coins. They will post a picture, have a slew of information, and then just the weight. Considering that the composition of coins varied hugely, saying that a coin is "4.3g" means almost nothing. I want diameters, gosh dern it. Oddly enough, those of the more "amateur" variety tend to list weight AND diameter. Why? 10 3 Quote Link to comment Share on other sites More sharing options...
hotwheelsearl Posted June 4 · Member Author Share Posted June 4 Auction houses be guilty too. https://www.numisbids.com/n.php?p=lot&sid=2518&lot=1051 This medallion is 6.08g, but...how big? I can try to estimate diameter based on density of relatively pure silver, but why can't they just tell me how big it is. This is such a pet peeve that drives me absolutely batty. 4 Quote Link to comment Share on other sites More sharing options...
mcwyler Posted June 4 · Member Share Posted June 4 45 minutes ago, hotwheelsearl said: Auction houses be guilty too. https://www.numisbids.com/n.php?p=lot&sid=2518&lot=1051 This medallion is 6.08g, but...how big? I can try to estimate diameter based on density of relatively pure silver, but why can't they just tell me how big it is. This is such a pet peeve that drives me absolutely batty. What a wonderful piece! But yeah I'd want to know how big before I paid that! Quote Link to comment Share on other sites More sharing options...
sand Posted June 4 · Member Share Posted June 4 (edited) I agree, that I like to see the diameter of the coin, in the description of the coin. Perhaps many persons, don't want to spend the time, to measure the diameter of the coin. And then, there is the question, of exactly how to measure the diameter of the coin, if the coin is not perfectly round, which is usually true for ancient coins and medieval coins. Whenever I post photos and a description of 1 of my coins, I like to measure the maximum diameter of the coin. That is, I measure the maximum distance, from 1 point on the edge of the coin, to another point on the edge of the coin. In my description of the coin, I give the maximum diameter of the coin, and I call it the "Maximum Diameter". That decreases the ambiguity, to a certain extent, of what the "diameter" is. However, one could disagree, about what the definition of "maximum diameter" is. For my definition of "maximum diameter", I don't require the maximum diameter to pass through the geometrical center of the coin. Other persons may have such a requirement. Edited June 4 by sand 2 Quote Link to comment Share on other sites More sharing options...
Benefactor Victor_Clark Posted June 4 · Benefactor Benefactor Share Posted June 4 17 minutes ago, sand said: I like to measure the maximum diameter of the coin. a better practice is to take the largest and smallest measurement and record it something like-- 24x26mm 4 1 3 Quote Link to comment Share on other sites More sharing options...
ACCLA-Mike Posted June 4 · Member Share Posted June 4 In my view, even worse is the trend to not listing the weights. Happens all too often with Heritage listings where they sell slabbed coins consigned by sellers who used the NGC cheapie encapsulation route. Really annoying. 5 1 Quote Link to comment Share on other sites More sharing options...
Dafydd Posted June 4 · Supporter Share Posted June 4 1 hour ago, hotwheelsearl said: I am not trying to call anybody out, but I have noticed an odd trend where some collectors of what I could consider the more "advanced" variety tend never to list the diameter of their coins. They will post a picture, have a slew of information, and then just the weight. Considering that the composition of coins varied hugely, saying that a coin is "4.3g" means almost nothing. I want diameters, gosh dern it. Oddly enough, those of the more "amateur" variety tend to list weight AND diameter. Why? I read your post @hotwheelsearl 2 minutes after posting a coin on the "Uno" thread without dimensions. I agree with you so rushed back and edited it with dimensions. I have no excuse only my insouciance because I use a database called Coin Organizer and the dimensions are stored on a separate page and I was in a rush to post. I think I will also add the dimensions to the bottom of the general description page too. I also agree with @Victor_Clark about being more specific about dimensions , something else that I only do if the coin is really irregular. In the past I have bought a couple of coins focused on a theme that I was keen to purchase and then been disappointed by their small size because the diameter had not been noted or my focus was on everything else if it had been. Quote Link to comment Share on other sites More sharing options...
Roman Collector Posted June 4 · Patron Share Posted June 4 (edited) I measure diameter from 9:00 to 3:00 on the obverse with a caliper. It may not reflect maximum diameter, but it's consistent. Edited June 4 by Roman Collector Quote Link to comment Share on other sites More sharing options...
John Conduitt Posted June 4 · Supporter Share Posted June 4 Quite a lot of coins are sold without the diameter so they don't get added. I think it's because the weight is considered more helpful in determining a fake or the denomination. A hammered coin will vary in width simply because it was hit harder, and is rarely round so that you usually have 2 or 3mm difference on the same coin. Having said that, weight isn't all that helpful in determining fakes with a lot of ancients, while diameter is obviously the most useful for visualising a coin posted on a forum. So I try to post both, although my diameters are much less precise. 4 Quote Link to comment Share on other sites More sharing options...
Heliodromus Posted June 4 · Member Share Posted June 4 2 hours ago, sand said: And then, there is the question, of exactly how to measure the diameter of the coin, For late roman bronze, but I'd assume also quite widely, the flan sizes (esp. post-strike) were not tightly controlled, but the die /design size was. For any given nominal weight standard there was an implicit corresponding die size. The critical measurement therefore is not diameter (or min/max diameter) of the flan, but rather the diameter of the beaded border (aka PRD = pearl-ring diameter) which will be fixed (within tolerance) for a given issue even when flan sizes, and poorly controlled flan weights, are all over the place. Listing the weight of an LRB is very rarely useful, except for making a gross distinction between nummus and and half-nummus, which is normally already evident. There are however a number of cases where the only way to tell the issue/date of a coin is by the PRD, which certainly makes it annoying when no measurement is given, not even an unspecified (min/max/random) diameter! 2 1 Quote Link to comment Share on other sites More sharing options...
Heliodromus Posted June 4 · Member Share Posted June 4 (edited) 3 hours ago, hotwheelsearl said: This medallion is 6.08g, but...how big? 24mm for what it's worth (although I realize that was just an example). What's interesting is that given the size one can therefore measure the Chi-Rho (one of the main points of interest) as only being ~1.5mm high. I have to wonder how many of the recipients examined the piece closely enough (and had good enough eyesight) to realize it was there ! Edited June 4 by Heliodromus Quote Link to comment Share on other sites More sharing options...
David Atherton Posted June 4 · Member Share Posted June 4 I'm guilty of this. The weight is very important, it can often help authenticating a questionable piece. I'll list the diameter if a coin is exceptionally smaller or larger than average, but generally it's not too important to me. The era of my specialty was fairly standard regarding diameter. 5 Quote Link to comment Share on other sites More sharing options...
Anaximander Posted June 4 · Member Share Posted June 4 I'm with @hotwheelsearl on this. I want the diameter, and I want the maximum diameter, so measure...measure...measure to get it right! I use digital calipers. While one decimal is probably sufficient when measuring millimeters, I don't mind going out to two decimals. And I do not round up. 14.258mm is 14.25mm. Talking about pet peeves, I will not be buying from one auctioneer that I tested out recently. They provided NO references, got the attribution wrong on TWO coins, and the auction wins showed up with NO dealer tag whatsover. Bare coin. Really? In this day and age? 4 Quote Link to comment Share on other sites More sharing options...
Sulla80 Posted June 5 · Supporter Share Posted June 5 5 hours ago, hotwheelsearl said: I am not trying to call anybody out, but I have noticed an odd trend where some collectors of what I could consider the more "advanced" variety tend never to list the diameter of their coins. They will post a picture, have a slew of information, and then just the weight. Considering that the composition of coins varied hugely, saying that a coin is "4.3g" means almost nothing. I want diameters, gosh dern it. Oddly enough, those of the more "amateur" variety tend to list weight AND diameter. Why? I tend to get lazy with diameter (not measuring) for RR denarii 18-20mm covers most of what I have - so unless it is something unusually large or unusually small I will skip. Weight and the scale of the coin on the flan are enough clue. That said - I prefer to see the diameter and even die axis when buying. 3 Quote Link to comment Share on other sites More sharing options...
CPK Posted June 5 · Supporter Share Posted June 5 I'm the same, I like to see diameter and weight and I list both in my own descriptions (along with the die axis.) I take the maximum diameter measurement. 1 Quote Link to comment Share on other sites More sharing options...
Hrefn Posted June 5 · Supporter Share Posted June 5 I have never measured the diameter of any of my coins. This thread has dealt a harrowing blow to my self-image. The damage is immeasurable. 1 1 1 2 1 1 1 Quote Link to comment Share on other sites More sharing options...
David Atherton Posted June 5 · Member Share Posted June 5 2 hours ago, Anaximander said: Talking about pet peeves, I will not be buying from one auctioneer that I tested out recently. They provided NO references, got the attribution wrong on TWO coins, and the auction wins showed up with NO dealer tag whatsover. Bare coin. Really? In this day and age? Personally, I like it when auction houses get attributions wrong, that's when you find cheap rarities. I never take a dealer's attribution at face value and ALWAYS double check it myself. 7 4 Quote Link to comment Share on other sites More sharing options...
NathanB Posted June 5 · Member Share Posted June 5 Oof! Feeling a little called out. 😉 And sometimes I don't even post the weights! 😄 That said, I think that's only when the picture is an illustration of something other than the coin--e.g., in the photography thread. That said, I do think it useful to have the diameter of a coin noted--especially when buying. And for rooting out fakes, you really need both diameter and weight (as well as knowledge about the coins fabric, striking, design, and so on). But I have seen silver modern silver coins faked with metals that get the weight more or less exactly right--but the diameter is completely off. More commonly, though, it's the other way around. One thing I have often wondered was how to measure the diameter of a coin. I've often assumed that I should go with the widest diameter, but I think that Heliodromus's post above has a good idea. Another thing to remember (assuming my memory is correct--someone more knowledgeable than I is welcome to correct me if I'm wrong!) is that quite often with ancient coins, a particular weight of liquid metal was supposed to be poured out so that each flan could have the same weight. But the flans weren't necessarily the same size. Furthermore, once you have the dies coming together in the hand-striking process, then no two will be exactly alike. So a weight is a closer, more objective measure of what the coin is and what it was supposed to be. It also has the virtue of indicating more or less exactly if something is missing. With diameter, meanwhile, who here measures the circumference of their coins in order to get an average diameter? And if you go with the widest diameter, that doesn't provide as usable a mental picture of how much of the coin is there in the same way that indicating the weight does. I don't know why I wrote any of that. From now on, I'll try to remember to post an approximate diameter by at least one method of calculation. 😉 3 Quote Link to comment Share on other sites More sharing options...
mc9 Posted June 5 · Member Share Posted June 5 For my own collection i always measure weight, diameter and thickness of a coin, holding the coin in the same position when measuring the thickness. 2 Quote Link to comment Share on other sites More sharing options...
seth77 Posted June 5 · Member Share Posted June 5 That's true, it's very annoying. At least use a banana for scale. 1 1 Quote Link to comment Share on other sites More sharing options...
hotwheelsearl Posted June 5 · Member Author Share Posted June 5 Lol, so glad this thread has spurred so much lively debate. For what it's worth, i have a clear plastic ruler that i lay over top of my coins, this lets me move it around until i find the dimensions that look right. 2 Quote Link to comment Share on other sites More sharing options...
Al Kowsky Posted June 5 · Member Share Posted June 5 14 hours ago, Victor_Clark said: a better practice is to take the largest and smallest measurement and record it something like-- 24x26mm The high & low measurement differences of a chord from the center of a circle is called roundness. The longest measurement of a chord from the center point of a circle is called the diameter. In manufacturing it's important to know the difference. Quote Link to comment Share on other sites More sharing options...
Benefactor Ancient Coin Hunter Posted June 5 · Benefactor Benefactor Share Posted June 5 (edited) I just use a metric ruler to measure if no diameter is given with the coin. I always record the size and weight of a coin on the paper envelope it is stored in. No flips or slabs in my collection anymore. The flips often crack or otherwise collect dust mysteriously. Plus, I live in a humid environment which means it is not healthy to store coins in plastic. That said I am often guilty of not posting the size or horror of horrors sometimes even the weight especially in those posts which say "show yours" where I am just casually posting a similar example to the OP. I probably should discontinue the practice and follow proper numismatic protocol. In the academic world this would be equivalent, perhaps, of not posting footnotes in a paper. I sincerely and completely apologize if I have ruffled feathers out there! 😇 Edited June 5 by Ancient Coin Hunter 1 Quote Link to comment Share on other sites More sharing options...
hotwheelsearl Posted June 5 · Member Author Share Posted June 5 For me, I always have a ruler or other measuring device at hand but not always an accurate 0.01g scale. Also, consider how different a coin of, Xgrams can be depending on thickness. An Alexandrian tetradrachm is extremely thick but relatively small in diameter, while you have rather broad flans of low weight, so the weight in these cases does nothing but confuddle 1 Quote Link to comment Share on other sites More sharing options...
akeady Posted June 5 · Supporter Share Posted June 5 I use one of these - the first hole the coin fits through is the diameter I record. I've always felt that the weight is a more important metric than the diameter, but everything is useful! by heart, I know the weights of the decimal pre-Euro coins and typical weights for a lot of Roman coins, but not the diameters. ATB, Aidan. 4 1 1 Quote Link to comment Share on other sites More sharing options...
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