Birthstones by month

Every month has at least one birthstone, and some months have two or three. The modern list used by most American jewelers goes back to 1912, when the National Association of Jewelers (now Jewelers of America) agreed on a standard set. It has been revised a few times since, and older traditional stones still appear alongside the modern ones.

The birthstone chart

The traditional column shows the stones that headed older lists before the 20th century revisions added alternatives. Bloodstone is a dark green chalcedony spotted with red, and sardonyx is chalcedony banded in reddish brown and white.

Where the birthstone list came from

The idea of linking stones to a calendar usually traces back to the breastplate of the Jewish high priest described in the Book of Exodus, which held twelve stones for the twelve tribes of Israel. Writers in the first centuries AD, including the historian Josephus and later St. Jerome, connected those twelve stones with the twelve months and the signs of the zodiac. For most of history people collected all twelve and wore the stone of the current month. The habit of wearing a single stone for your birth month is usually traced to Europe, with Germany or Poland named as its likely starting point sometime between the 16th and 18th centuries. The gemstone meanings and folklore page covers the older beliefs attached to each stone.

Because the ancient stone names did not always match modern minerals, lists drifted from country to country. By the early 1900s American jewelers wanted a single list they could sell from, and the 1912 meeting in Kansas City produced it.

How the modern list changed

The list has not stood still since 1912. These are the main changes on the American list:

1. The 1912 list gave most months one stone and a few months an alternate: bloodstone or aquamarine for March, pearl or moonstone for June, sardonyx or peridot for August, opal or tourmaline for October, and turquoise or lapis lazuli for December.
2. In 1952 the Jewelry Industry Council revised it. Alexandrite joined June, citrine joined November, and zircon replaced lapis lazuli for December. Aquamarine became the main March stone and peridot the main August stone, with bloodstone and sardonyx kept as alternates.
3. In 2002 the American Gem Trade Association added tanzanite to December, a little over three decades after the gem was found in Tanzania.
4. In 2016 the American Gem Trade Association and Jewelers of America added spinel to August.

Other countries keep their own lists. The British list, set by the National Association of Goldsmiths in 1937, differs in a few months, and some Asian traditions follow different systems entirely. The chart above follows the modern American list, which is the one most often quoted.

Why some months have several stones

Extra stones usually entered the list for practical reasons. Some traditional stones were rare, expensive or hard to wear, so the trade added a second choice. June shows this well: natural pearls were costly and fragile, so moonstone and later alexandrite gave buyers options at different prices and hardness levels. December gained zircon and tanzanite partly because turquoise is opaque and soft, and some buyers wanted a transparent blue stone. August gained spinel because peridot has a limited color range and sardonyx is an opaque banded stone few people associated with fine jewelry.

Having several stones also lets you choose by color. October can be the play of color in opal or a pink, green or bicolor tourmaline. November covers golden topaz and citrine, which can look alike.

Durability: which birthstones wear well

Birthstones often end up in rings worn every day, so hardness and toughness matter. The Mohs hardness scale gives a quick guide, and anything below 7 can be scratched by ordinary household dust, which contains quartz.

• Diamond (10), ruby and sapphire (9) and alexandrite and spinel (8 to 8.5) suit everyday rings.
• Garnet, amethyst, citrine, aquamarine, emerald, tourmaline and zircon fall between 6.5 and 8. They are fine for rings with some care, though emerald often has fractures and zircon can chip at facet edges.
• Topaz is hard at 8 but has perfect cleavage, so a sharp knock can split it.
• Peridot (6.5 to 7) and tanzanite (6 to 7) scratch more easily, and tanzanite also has cleavage.
• Opal, moonstone and turquoise sit around 5 to 6.5. Pearl is only 2.5 to 4.5. These work best in earrings, pendants or protective settings.

The gemstone durability guide goes further into toughness and stability, and the jewelry cleaning page explains which birthstones can go in an ultrasonic cleaner and which cannot.

Natural, treated and lab-grown birthstones

Many birthstones are routinely treated. Most blue topaz is irradiated, most tanzanite is heated, many rubies and sapphires are heated, and emeralds are commonly oiled. Lab-grown versions exist for ruby, sapphire, emerald, alexandrite, spinel and quartz, and they are often sold in birthstone jewelry. Under U.S. Federal Trade Commission guidance, sellers should disclose treatments that affect value or care and should clearly label lab-grown stones. See how to buy a gemstone before paying for a more expensive piece.

Frequently asked questions

Who decides the official birthstones?

No government sets them. In the United States the list comes from jewelry trade groups, starting with the National Association of Jewelers in 1912 and later the Jewelry Industry Council, the American Gem Trade Association and Jewelers of America.

Why does December have three birthstones?

Turquoise has been the December stone since the 1912 list. Zircon was added in 1952 and tanzanite in 2002, giving buyers transparent blue options.

When was spinel added as a birthstone?

Spinel was added to August in 2016, joining peridot and sardonyx.

Which birthstones are best for an everyday ring?

Diamond, ruby, sapphire, spinel and alexandrite are the hardest and toughest choices. Opal, pearl, turquoise and moonstone need more protection.