What is the IGSN?

IGSN stands for International Geo Sample Number. The IGSN is an alphanumeric code that uniquely identifies samples taken from our natural environment (for example: rock specimens, water samples, sediment cores), as well as related sampling features (sites, stations, stratigraphic sections, etc.). Except in special cases*, IGSNs obtained from SESAR are 9 characters long. IGSNs obtained from allocating agents other than SESAR may have different syntax, but all are guaranteed to be globally unique via a central registry.



1) IGSN:HRV003M16   (Registered object: Malachite specimen from Angola, registered by the Mineralogical Museum of Harvard University)

2) IGSN:WHO000BC7  (Registered object: Dredge CHAIN35-2 St18 D18, registered by the Woods Hole Oceanographic Institution)

3) IGSN: IECUR0002 (Registered object: Metamorphic rock powder from Australia, registered by Curtin University)


Syntax for IGSNs from SESAR:

The IGSN is a “mostly unintelligent” identifier. For namespaces assigned after June 2014 (e.g. example #3 above), the first five characters of the IGSN represent a name space (a unique user code) that uniquely identifies the person or institution that registers the sample. The first two characters will be IE, followed by 3 characters of the registrant's choosing. The last 4 characters of the IGSN are a random string of alphanumeric characters (0-9, A-Z). The IGSN follows the syntax of the URN (Uniform Resource Name) which is composed of a ‘Namespace Identifier' (NID), a unique, short string, and the ‘Namespace Specific String’ (NSS).


The length of the IGSN has been limited to 9 characters to keep it short enough for use on sample labels and for inclusion in data tables of publications (the number of characters is similar to data, for example, Sr isotope data typically use a 8 character string such as 0.703456). The IGSN is long enough for large institutions such as repositories or museums to register large numbers of samples (with 10 numbers plus 26 letters for the 4 random characters after the user code, a total of 36^4 = 1,679,616 sample identifiers per namespace are available).


IGSN namespaces that were obtained before July 2014 may have three character namespaces followed by a random string of 6 alphanumeric characters (e.g. examples #1 and # 2 above). For more information see http://www.geosamples.org/news/namespacechanges.


*Starting in July 2017, SESAR users were allowed to register samples with IGSNs of up to 32 characters in length (0-9, A-Z, '-', '.'). This syntax follows recommendations of the IGSN e.V. at http://igsn.github.io/syntax/. The extended syntax is primarily intended for use by large repositories, where it may be necessary to use hierarchical syntax conventions. However, with human readability in mind as well as the fact that the IGSNs appear on-line and in print, the IGSN e.V. recommends that the IGSN should be as concise as possible. If you are considering assigning IGSNs to your samples that are longer than 9 characters, please contact info@geosamples.org to discuss.


Why do we need the IGSN?

What are the benefits of the IGSN?

How should the IGSN be used?

How do I obtain an IGSN?