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 Replies: 16 / Views: 4,021 |
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New Member
United States
4 Posts |
A couple weeks ago, I ordered a 1/4 troy ounce .9999 gold round from APMEX: http://www.apmex.com/product/57381/...nd-9999-fineWhile I was waiting, I decided to do a simple density calculation, assuming that the round can reasonably be approximated as a cylinder. The density of gold, in the solid state, is 19.3 gram/cm^3. There are 31.1. grams per troy ounce, so the round is 0.25 X 31.1. g/ozt = 7.78 grams. The page linked to above states the diameter is 21.87 mm, which is 2.187 cm, and the thickness is 2.6 mm = .26 cm. The volume of a cylinder is pi * radius^2 * thickness, which for this round would be .977 cm^3. The overall density of the round is then 7.78 grams/977 cm^3 = 7.96 g/cm^3. 7.96 g/cm^3 versus 19.3 g/cm^3. That's less than half. This only leaves two possibilities: (1) My assumption that the round can be reasonably approximated as a cylinder is incorrect. (2) The item is not .9999 gold. I really cannot see a reputable company like APMEX doing # 2, so the only think that comes to mind is that there the round is either partially hollow, or perhaps the round is tapered as you move towards the center (e.g., non-uniform thickness). To the naked eye, the round looks very close to being a perfect cylinder, so I am wondering if there is an empty space inside, but that begs the question of why that would be done. I called APMEX up, and the representative said that he would ask a supervisor about it, and in the meantime directed me to the website of the Sunshine Mint (which is currently down), the party that makes the product that I bought. Any help in solving this mystery would be greatly appreciated. |
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Pillar of the Community
United States
1200 Posts |
1---Welcome to CCF.
2---The round is stamped. "Rim thickness" will be the widest point in the entire round and very little of the remainder of the item will be at (or maybe even near)
the APMEX-cited thickness of 2.6mm.
3---APMEX is hopefully about as reasonably reliable as could be hoped for in the PM world. I think the probability of your getting stiffed in buying one of their
own 1/4oz gold rounds is close to zero.
4---If you put this intensity of verification calculations into validating every piece of PM that you buy, you'll drive yourself crazy and probably have a stroke
long before you accumulate even one tube full of coins/rounds.
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Valued Member
United States
456 Posts |
Welcome EE78! I think your assumption is fine. It will be a little off (low), but it should get you close. Compared to a cylinder there will be differences in thickness based on the rim height and the diameter due to reeding (if it has it). Clearly there is something amiss calculating a density of 8 g/cc rather than 19. I think the problem is with the thickness. APMEX states a thickness of 2.6 mm which seems highly unlikely considering their 1/2 oz gold round has a thickness of 1.7 mm. I'm betting that's a typo and should be about half of that. Can you measure it and see? Check your calculations using the dimensions given for the 1/10 and 1/2 oz APMEX gold rounds and you will see your assumption gets you much closer to the density of gold. |
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Pillar of the Community
United States
808 Posts |
Welcome EE78! You've already gotten some pretty good technical replies to your APMEX gold round question so I'll just throw out my .02 cents on a different issue. If you have any doubt at all about your round, I'm certain that APMEX will take it back. I've used APMEX off and on for a long time now and, while they aren't the cheapest (especially those high shipping fees), they have very reliable customer service. I've had to send back exactly one coin to them and they took very good care of me. Life is way to short to worry about a coin. Sent it back, let APMEX make it right, and be happy! Edited by coinwatch
07/08/2013 4:38 pm
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Valued Member
United States
456 Posts |
I contacted APMEX through a chat, and was informed the product manager said he had written down the thickness was 2.6 mm. After looking at examples such as the Philharmonic, which has a similar diameter and only a thickness of 1.2 mm, the product manager was going to have someone get one from the vault, remeasure, and update the website if (when) necessary. They said to check the website within 24 hours for an update. |
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New Member
 United States
4 Posts |
Thank you for your replies! I took a crude measurement with a tape measure, and it is indeed just over 1 mm. I think that that solves the mystery, as according to my calculations, a mean thickness of about .11 cm (e.g., 1.1 mm) yields the appropriate volume for a density of 19.3 g/cm^3. Thank you SDCrow!
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Pillar of the Community
United States
1200 Posts |
This thread got me curious, so I checked the APMEX-posted dimensions of 1/4oz gold pieces and found -- AGE = 22mm x 1.83mm; CGM = 20mm x 1.7mm; Philharmonic = 22mm x 1.2mm; Panda = 21.95mm x 1.53mm and APMEX Round = 21.87mm x 2.6mm. At this point, I wish I hadn't done the research. If I was a fractional gold stacker, widely disparate and seemingly contradictory dimensions like those would be enough to make me stick with PAMP bars in assay cards. |
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Valued Member
United States
456 Posts |
No problem EE78. Glad to have you here. I hope you'll stick around. Ha FF! I think reeding leads to the disparity between the Phil and the others. The APMEX round should be in line with the Phil based pm EE78's measurement. The panda and maple are close enough to each other considering the diameter difference. Remember, the eagles are 22 karat, so they'll be a little bigger to account for the added Ag and Cu. |
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New Member
United States
4 Posts |
"No problem EE78. Glad to have you here. I hope you'll stick around." I will! "Ha FF! I think reeding leads to the disparity between the Phil and the others. The APMEX round should be in line with the Phil based pm EE78's measurement. The panda and maple are close enough to each other considering the diameter difference. Remember, the eagles are 22 karat, so they'll be a little bigger to account for the added Ag and Cu." Reeding is probably part of it, but my guess is that the lip (for lack of a better word) at the rim is probably quite pronounced on some rounds and less so on others (it's actually not very pronounced on the round referred to in the OP). |
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New Member
United States
4 Posts |
"I contacted APMEX through a chat, and was informed the product manager said he had written down the thickness was 2.6 mm. After looking at examples such as the Philharmonic, which has a similar diameter and only a thickness of 1.2 mm, the product manager was going to have someone get one from the vault, remeasure, and update the website if (when) necessary. They said to check the website within 24 hours for an update." I found a caliper and measured it: 1.3 mm. I wonder if someone measured two of them at once?! Anyway, it's been more than 24 hours and they haven't changed the thickness value. |
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Pillar of the Community
United States
808 Posts |
Depending on who maintains the company web site, not to mention their internal change request policies, it very well may take more than 24 hours to make even such a minor change. Not making excuses for APMEX here. This is just my experience in the corporate world. If you're concerned about letting other potential buyers know the size problem, I'm pretty sure there's a ratings and reviews section of the product page. Just post your experience there with the correct size of the round. |
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New Member
United States
1 Posts |
EE78..
Your second statement is correct. (2) The item is not .9999 gold..
The round in the link you shown is not .9999 fine. .9999 is about 24-carat if I remember correctly. I have purchased the gold round my self the same exact one. and ran it though a acid test and found how it had failed down 22k solution,18k solution down to the 14K!!. Meaning it is only about half real true blue gold. Not only did I test, but I purchased another exact same round and sent my and the new purchase to my local gold shop (Texas Gold Lady)(in Sherman, Texas) and she conducted tests and came to same conclusion because of it failing her tests as well.
FRAUD..
*** corrected word usage ***
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Pillar of the Community
United States
561 Posts |
I hate a failed test!
*** removed use of adult term from previous post that was corrected ***
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Pillar of the Community
United States
3670 Posts |
Wow! Are you trying one up Einstein's theory of relativity or buy pmz lol?
Just razzin ya welcome to the site.....
Here is a great calculus formula that may seem like smart Alex reply now but a few years down road you will thank me ;)....
KISS=Keep it simple stupid....
Edited by Silverhawk74
08/28/2013 11:36 pm
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Pillar of the Community
United States
3670 Posts |
"Your second statement is correct. (2) The item is not .9999 gold.. The round in the link you shown is not .9999 fine. .9999 is about 24-carat if I remember correctly. I have purchased the gold round my self the same exact one. and ran it though a acid test and found how it had failed down 22k solution,18k solution down to the 14K!!. Meaning it is only about half real true blue gold. Not only did I test, but I purchased another exact same round and sent my and the new purchase to my local gold shop (Texas Gold Lady)(in Sherman, Texas) and she conducted tests and came to same conclusion because of it failing her tests as well. FRAUD.." However no science like real evidence and that is interesting. REAL surpirsed APMEX of all places like kings of the PM world would be guilty of such, makes ya wonder lol.... Edited by Silverhawk74
08/28/2013 11:37 pm
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Pillar of the Community
United States
561 Posts |
It's cool if the mods are going to edit posts to conform to forum rules and such but you should at least leave indication of such on the post instead of just making the changes. Makes it difficult to know who is posting what.
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Replies: 16 / Views: 4,021 |
Posted 07/08/2013 4:24 pm
