methodology — accession, analysis, retention
identifier scheme
Identifiers take the form AM-YYYY-NNNNN-X:
| AM | fixed registry prefix |
|---|---|
| YYYY | year of first accession (UTC) |
| NNNNN | five-digit sequence within the year, zero-padded |
| X | analytical pass under which the record was created (A, B, C…). A subsequent pass on the same physical specimen receives a new suffix and a new record. |
passes
| pass A | visual inspection, mass, density estimate |
|---|---|
| pass B | raman spectroscopy (532 nm), occasionally 785 nm |
| pass C | x-ray diffraction (Cu Kα), where instrument access permits |
| pass D | electron microprobe (when externally arranged) |
submitter anonymity
Submitters are identified internally by a six-character truncation of a SHA-256 hash of their submission packet metadata. The full hash is retained but not published. A value of REDACTED in the submitter field indicates that the submitter has invoked their right to post-hoc anonymisation under the registry's standing data policy.
retention
Once accessioned, records are retained indefinitely. Withdrawal does not delete a record; it removes it from active circulation and flags it as historical. Records are revised rather than overwritten; revision history is available on request.
indexing integrity
Each catalogue entry is associated with a content-addressed identifier (the proof-hash), computed as a SHA-256 digest over the canonical serialisation of the record's primary metadata (accession identifier, designation, formula, locality, submission date, submitter hash, and record revision) concatenated with the proof-hash of the immediately preceding entry under the canonical submission ordering. The first record in the registry is bound to a fixed registry-wide constant, designated the genesis-hash, derived from the registry's founding date.
This construction allows independent verification that no historical record has been silently altered: any modification to a single entry — including a single character of its serialisation — invalidates the proof-hash of that entry and, by transitive dependence, every proof-hash that follows. The complete sequence is exposed alongside each public record and is republished in full at each periodic export of the catalogue. Outside readers wishing to verify the chain may recompute it from the genesis-hash given below; no privileged access is required.
| algorithm | SHA-256, 256 bits |
|---|---|
| canonicalisation | UTF-8 JSON, fields in fixed order |
| chain ordering | ascending by dateSubmitted, ties by accession |
| genesis-hash | 942634f3a3a6f6605db62340b975a4050ec7ef827112b929a87b5a82e9cc4d06 |
| current head-hash | ab9b0060d2e5d39012d012f99dcfda64b18583697ef37319bf989815751a827d |
The integrity construction described here was introduced with the 2014 reorganisation of the catalogue and applied retroactively to all prior records in their then-current form. Records accessioned before that date carry, in addition to their proof-hash, an archival reference to the printed accession book in which the original entry was made.