The 2009 Project Mayhem article on Zero Hedge (original article, plus my backup copy) was to my knowledge the very first example of proper 'barspotting' - their document attempted to explain the presence of 'duplicate serial numbers' in the SLV data. A few times I have been tempted to adopt their classifications for my study but found them unworkable - the only real definition of significance is their 'Perfect Internal Duplicate' (match on serial number, weight, brand) but their study failed (IMO) due to bias but the effort was still a stepping stone in barology.
Finding a truly unique bar number is difficult because it is known that some refiners restart their numbering sequence (like Tanaka gold bars). Additionally, there is no standardization on Refiner names or codes and even the weights will sometimes vary - e.g. bars being delivered to GLD sometimes have weight inconsistencies and this may vary from vault to vault.
|Close-up from the Bob Pisani sequence - correct bars weights have a tick ...|
but some other bars show up as a different weight to six significant figures.
- Serial Number
Let's rework this with a bit more detail to get the rough parts. I'm also rearranging them in order of what I think works. Please bear in mind I am not a member of the international standards organization ; p
- Refiner/Brand - as a four-letter alphanumeric code. Currently there is no standard universal code list but the best one is from CPM GROUP. Using this consistently would require the establishment of codes for the historical refineries and published somewhere permanent (which would be challenging). In the case of similar names, a number can be used in the fourth position.
- Year (of manufacture) - where available. Four digits for simplicity, follows a formatting convention that most people are familiar with: YYYY. Where the full or exact year record is not available or known, "0000" should be used.
- Purity/Assay/Fineness - expressed to four significant figures where possible. If the fourth digit is not known or is not available, an "X" should be used (rather than zero) to indicate the value was not recorded. This will force the fineness to be evaluated as text rather than a number.
- Weight (Gross) - I have elected Gross weight as being the unit of measure because in the case of gold bars, the fine weight can be determined using the fineness/assay (and in the case of the lesser metals, a Fine weight is not recorded). Silver is typically only recorded to one decimal place, but gold has three decimal places so that will be the standard. Finally, silver has weights up to 1000 oz so we'll use seven significant figures. Measurement is in OZ, since that's the obvious industry standard. This does mean that some platinum bars measured in kg cannot be stored.
- Serial Number - As appears on the bar list. Note: The fullest bar serial number seen should be used. i.e. leading zeroes included where they are recorded (even if removed later) and year included as the prefix where it has been included in the records, even if this duplicates the information in year of manufacture. Because the serial number is variable length, it will be placed last so that the positioning of all the other information is consistent.
^^ This refiner is OJSC Krasnoyarsk bar as identified by their 'Россия' stemp, and while theirs is not in the CPM Group listing, the most obvious four-letter code is OJSC. The year of manufacture (6) we only know from pictures like these and fortunately we have records in the bar list which measure the weight in oz. The universal bar number is:
^^ Rand Refineries bar, which allows us visiblity to the year of manufacture (which may also apply for most of the 'ZA' series). The weight and fineness is known from the bar list data. Universal bar number is:
^^ A picture Bron sent me of a (beautiful) old silver bar, recently recovered from the seabed floor from a sunken WW2 ship. This bar is (obviously) not registered in any ETF records, and even the refiner (Indian Government Mint) is not seen in any modern records. Nonetheless with our numbering system we should still be able to catalog it, something like:
Update: 22nd April 2014.
Added Bron's suggestion (Below) regarding currency code prefix, samples in this article become:
Now just gotta work on the delimiter. And also addition of other information like 'obsolete/superceded/dead' bar signature (probably as a suffix).