Explainer · Plain-language

The Igsn: Definition, Meaning & Examples | CASRAI

The IGSN is a persistent identifier for physical samples and specimens — such as rocks, sediment cores, water samples, and biological specimens. It gives a tangible object a globally unique, citable identity, so that the sample behind a measurement can be tracked, referenced, and linked to the data and publications derived from it. Since 2021 IGSN IDs have been issued through DataCite as a specialised use of its DOI infrastructure.

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Why physical samples need identifiers

Much research rests on physical samples — a sediment core, a mineral specimen, a water or tissue sample — that are measured, sub-sampled, archived, and revisited over many years. Without a stable identifier, the same sample can be described inconsistently across labs and papers, making it impossible to know whether two results refer to the same object. Sub-samples and derived measurements compound the problem. The IGSN solves this by assigning a single, persistent, globally unique identifier to a sample. Every analysis, dataset, and publication that uses the sample can reference the same identifier, so the full chain from a physical object to the digital results derived from it can be traced and reconstructed.

From sample number to DataCite DOI

The IGSN began in the geosciences as a way to register Earth and environmental samples. In 2021, IGSN e.V. (the organisation governing the identifier) entered a partnership with DataCite so that IGSN IDs are issued as DataCite DOIs. This means an IGSN now sits on the same persistent-identifier infrastructure used for datasets and other research outputs, gaining robust resolution, a metadata schema, and interoperability with the wider PID landscape. The broadening of the acronym from "Geo Sample Number" to "Generic Sample Number" reflects that the identifier is intended for physical samples across disciplines — geological, environmental, and biological — not just the geosciences in which it originated.

Registering samples and SESAR

Samples are registered with the help of allocating agents and registration systems that mint identifiers and host the descriptive metadata. SESAR, the System for Earth Sample Registration, is a long-standing example: it operates a catalogue where researchers register samples and receive identifiers, recording details such as the sample type, the collector, and the location and time of collection. The registered metadata is what makes a sample identifier useful: it describes the object, where it sits in a collection or archive, and how it relates to parent samples and sub-samples — so that a citation resolves not just to a code but to meaningful information about the physical specimen.

The IGSN and FAIR

Assigning a persistent identifier to a physical sample is a precondition for making sample-related information FAIR. The identifier makes the sample Findable and, through resolvable metadata, supports Accessibility and the documentation needed for Reuse; aligning on shared schemas supports Interoperability across collections and disciplines. By linking samples to the data and publications derived from them, the IGSN connects the physical and digital research records. It lets a reader move from a published result back to the exact specimen it came from, strengthening reproducibility and enabling the reuse of valuable, often irreplaceable, physical samples.

Key facts

At a glance

Definition: A persistent identifier for physical samples and specimens
Stands for: International Generic Sample Number (formerly Geo Sample Number)
Infrastructure: Issued as DataCite DOIs since the 2021 partnership
Registration: Via allocating agents and systems such as SESAR
Covers: Geological, environmental, and biological samples
Purpose: Brings physical objects into the FAIR data ecosystem

Common misconceptions

What people often get wrong

Often heard: The IGSN identifies a dataset about a sample.

Actually: No — it identifies the physical sample itself. The data measured from that sample are separate outputs, which can be linked back to the sample through its IGSN.

Often heard: IGSN is a completely separate system from DOIs.

Actually: No — since the 2021 DataCite partnership, IGSN IDs are issued as DataCite DOIs, so they run on the same persistent-identifier infrastructure as datasets and other outputs.

Often heard: The IGSN is only for geological rocks.

Actually: No — although it began in the geosciences, the "Generic" in its expanded name reflects its use for environmental and biological specimens too.

Going deeper