Morgan weight...how exact to 412.5 grains/26.73 grams is ok? 0

[PNGento]

So, I have two Morgans I received from an auction.  First time I've gotten raw, ungraded/unslabbed coins.  One, the more mint state, shows 411.4 grains/26.65 grams.

The other, I would say is, at worst, very lightly circulated...it shows 411.6 grains/26.67 grams.  I cannot see anything that would make me believe either is counterfeit, but then I'm not sure I would recognize a counterfeit to begin with.  I have a professional grade binocular microscope, so I can get 10X to 60X of excellent magnification.  I see nothing that would concern me, other than the weight (hence the question).

Both had the correct "ringing sound" I would have expected, and a neodymium magnet slowly slide off when coin was held at 45 degrees, so both of those tests were ok.

Edited November 1, 2022 by PNGento
Added some additional information

[JKK]

20mg is a pretty small amount. I'd think even a little bit of atmospheric patina could make up something like that much. As they circulated--if they had circulated more--they would eventually lose over 5% of total weight on their way to AG-3 flatness. Obviously without photos we can't say jack about whether they're authentic, but the fact that both are a little light of 26.73g suggests that both are a little more worn than you might perceive. I don't recall what the tolerance is offhand, but I suspect both are within it.

[EagleRJO]

The tolerance of the 26.73g weight spec for a Morgan is +/- 0.097 grams (or +/- 0.10 grams rounded) so it should be between 26.63g and 26.83g. Seems normal being a little under as opposed to being a little over and wasting silver, particularly with a little wear. You can also check the diameter at 38.1mm, thickness at 2.9mm and SG at 10.34 (no stated tolerance, so just use the significant figures). If you know the series and it looks legit, but you want to be more cautious you can also go to VamWorld.com and identify the VAM from the date/mark positions and the die markers. It is hard to replicate the die markers.

Edited November 3, 2022 by EagleRJO

[RWB]

This little table will help. PS: If anyone wants a PDF of the table, send me your email. RWB

Edited November 3, 2022 by RWB

[EagleRJO]

@RWBThanks for sharing that table! I did notice one typo maybe from transcribing or from the original documents is that a 412.5 grain silver dollar is 0.8594 troy ounces (or 26.73g), not 0.8994 troy ounces. The thickness also looks off as I have a table with 2.9mm, which has been a match with many I have but this may just be an edge thickness spec. Interesting that there are wear tolerances for gold which I didn't know were available. Also, have you been able to discover any tolerances for the diameter (or thickness, but that is not a mint spec) which I have not been able to locate.

Edited November 3, 2022 by EagleRJO

[RWB]

This one from about 1930 might help. Diameter of coins after about 1895 is slightly greater on one rim than the other. This is due to the conical shape of the collar and the drift tool used to add reeds. For coining force ("pressure") the critical quantity is tons per square inch,

Edited November 2, 2022 by RWB

[EagleRJO]

@RWBVery interesting ledger from the Philly mint, thanks for sharing! Seems like you have a digital museum of coins. 

Looks like the leger data for a period silver dollar is consistent with the data I have including the 1.50" or 38.1mm average diameter and 0.114" or 2.90mm thickness (which was my post typo, corrected). It does look like the weight of a period silver dollar is 0.859375 (0.8594 rounded) troy ounces from the ledger which is or 412.5 grains or 26.73 grams which matches the table data I have, so that 0.899375 entry in the spreadsheet posted previously does look like a typo.

[RWB]

Yep. Having eleven toes will do that when typing. Corrected table is posted. Thanks.

[EagleRJO]

I find historical stuff about coins like the old ledger very interesting. Can I borrow your hard drive. 

Edited November 3, 2022 by EagleRJO

[RWB]

On 11/3/2022 at 9:54 AM, EagleRJO said:

I find historical stuff about coins like the old ledger very interesting. Can I borrow your hard drive. 

You'll need abut 2 Tbytes for the database.... 

My files, including earlier paper photocopies that have yet to be digitized, mirror my research approach. This is: pull boxes and volumes, scan and record general content and date ranges, copy everything that might have a use for either a current project or something in the future....that is, don't out guess myself. Every page of every document is labeled with its NARA location and file ID. Every individual document that I read is given a name based on date and content. My search engine indexes everything and allows searching by file name words, ID, date, OCR text, etc.  An example: for the S-G Double eagle book, which took a year to write, I went back to materials I'd discovered more than 10 years before at NARA, LoC, Royal Mint, US Treasury, Sec of Treasury, Comptroller of Currency, Commerce Dept, Insular Affairs, French National Archives, etc. None of this had much relevance when copied -- but was there, waiting for the DE book project.

I'll email you a copy of my research methodology representation given at ANA and other clubs. It might be helpful to you in the future.

[VKurtB]

Roger, I just thought I’d give you the citation where the authors of Mega Red #6 make the case that 1964SMS coins are a real thing. When one CAREFULLY parses the language, it’s filled with mealymouth words, but it’s page 799-800. 

[RWB]

Thank you! Lots of "mealy worms" to justify a false attribution, and a failure to accept responsibility thereafter.