The 1912 standardised birthstone list adopted at the annual convention, Kansas City

The 1912 standardized birthstone list, adopted at the annual convention of the National Association of Jewelers, now Jewelers of America, is a primary trade-industry source, the actual document that fixed the modern month-by-birthstone associations still widely used today. As the trade body's own founding standardization record, it is directly authoritative for when and by whom the now-familiar list was formally codified, superseding the considerably more variable birthstone traditions that had circulated informally before it. It is a commercial trade association's marketing standardization, not a record of ancient or continuous religious tradition, and treating the 1912 list as older or more historically rooted than a twentieth century jewelers' convention decision would misrepresent what this source actually documents.