What is the rarest birthstone?

The rarest birthstone by people: amethyst

Everyone born in a month shares its birthstone, so a birthstone is exactly as common as its month. February had the fewest U.S. births from 2000 to 2014, 4,725,693 of 62,187,024, so amethyst is the birthstone the fewest people share: 7.60%, about 1 in 13. It was last in 2024 too, at 7.80%. The reason is the calendar: February has 28 or 29 days. Diamond (April, 7.98%) is next, and peridot and spinel (August, 8.91%) are shared by the most.

No birthstone is rare in this sense: every month holds between 7.60% and 8.91% of births. Per day, January has the fewest, 10,909 births a day, so garnet is the quietest birthstone by day of the month. The birth month ranking has every month per day and in total.

The rarest birthstone as a gem

GIA, the Gemological Institute of America, does not rank birthstones by rarity, so neither do we. Two stand out in its own words. Tanzanite, one of December’s three: “Commercially mined in only one place, tanzanite is rarer than diamond.” Alexandrite, one of June’s three, is “the very rare color-change variety of the mineral chrysoberyl,” and “fine material is exceptionally rare and valuable.” The table above collects what GIA says about rarity, stone by stone.

Amethyst is the reverse case. GIA notes that it was once as rare as ruby or emerald, until large deposits were found in Brazil in the 19th century; now it is “within reach of most consumers.” The birthstone the fewest people share is one of the easiest to buy.

Which birthstone list we use

The official U.S. list comes from Jewelers of America, which created it in 1912 as the American National Retail Jewelers Association; the chart follows it. The American Gem Society and GIA list the same stones and also keep bloodstone for March and sardonyx for August, which GIA calls “the original August birthstone.” The chart shows both as also listed. All three lists include spinel for August and tanzanite for December. Jewelers of America names blue zircon for December, where the other two say zircon.

Each month in the chart links to its birthday page, which ranks every date and names the month’s birthstone. The birthday calculator shows how rare your own date is.

Sources

Birthstone lists and quotes: Jewelers of America, the American Gem Society and GIA’s birthstone pages and gem encyclopedia (tanzanite, alexandrite, spinel), all read October 11, 2026. Births: SSA counts compiled by FiveThirtyEight (CC BY 4.0) for 2000–2014 and the NCHS natality public-use file for 2024, shown side by side and never combined. The methodology has the detail.