Birthstones by Month: Meanings and Care

Quick answer: the modern U.S. list runs garnet (January), amethyst (February), aquamarine and bloodstone (March), diamond (April), emerald (May), pearl, moonstone and alexandrite (June), ruby (July), peridot, spinel and sardonyx (August), sapphire (September), opal and tourmaline (October), topaz and citrine (November), and turquoise, zircon and tanzanite (December). Care depends on hardness and treatments, so soft or treated stones such as pearl, opal, emerald and turquoise need the gentlest cleaning.

Birthstones are one of the oldest ways people connect gems to a personal story. A ring set with a child’s birthstone, a pendant for a partner’s month, or a single tumbled stone on a desk can feel more personal than any other piece of jewelry. Behind the sentiment, though, each stone is a real mineral or organic material with its own strengths and weak points.

This guide walks through the list month by month. For each stone you will find what it is, its approximate Mohs hardness, the traditions attached to it and the care it needs. Traditional meanings are described as folklore and beliefs, not proven effects.

Many of these stones have full profiles of their own, and the series as a whole is organized in our crystal meanings guide, which explains hardness, cleansing and how to spot fakes.

Where the Birthstone List Comes From

The idea of twelve special stones is ancient. The Book of Exodus describes a breastplate worn by the high priest Aaron, set with twelve gems representing the tribes of Israel. In the first century, the historian Josephus connected those twelve stones with the twelve months and the signs of the zodiac, and later writers, including Saint Jerome, made similar connections.

Wearing a single stone for your birth month came much later. The Gemological Institute of America (GIA) notes that the custom became popular in recent centuries, and the gem scholar George Frederick Kunz discussed its history in his 1913 book The Curious Lore of Precious Stones.

The Modern List

The list most American jewelers use today dates to 1912, when the National Association of Jewelers, now Jewelers of America, adopted an official version. That list has been updated several times since. The American Gem Trade Association added tanzanite as a December birthstone in 2002, and in 2016 the AGTA and Jewelers of America added spinel to August. Other countries and traditions use different lists, and some people prefer older “traditional” or zodiac-based lists, so there is no single correct answer.

A Quick Word on Hardness

The Mohs scale ranks resistance to scratching from 1, talc, to 10, diamond. Ordinary dust contains quartz, which rates 7, so stones softer than 7 slowly lose their polish when worn often. Hardness is not the same as toughness. A diamond is the hardest natural material, but it can still chip if struck along a weak plane.

January to April

January: Garnet

Garnet is not one mineral but a group of closely related silicate minerals, including almandine, pyrope, spessartine, grossular and andradite. Most garnets rate about 6.5 to 7.5 on the Mohs scale. Deep red is the familiar color, yet garnets also come in orange, green and even color-changing varieties. In folklore, garnet was carried as a travel talisman believed to protect against harm. Warm, soapy water and a soft brush are safe for most garnets. Our garnet guide covers the varieties in more depth.

February: Amethyst

Amethyst is purple quartz, rated 7. Its color, GIA explains, comes from iron impurities combined with natural irradiation. Ancient Greeks linked it with sobriety, and the name comes from a Greek word often translated as “not intoxicated.” Long exposure to strong sunlight can fade amethyst, so store it away from bright windows. The amethyst profile explains color grades and common fakes.

March: Aquamarine and Bloodstone

Aquamarine is blue to greenish blue beryl, the same mineral species as emerald, with a hardness of about 7.5 to 8. Iron gives it color, and many stones are heat-treated to remove a green tint and leave a purer blue. Its name comes from Latin words for “seawater,” and sailors’ folklore treated it as a charm for safe voyages.

Bloodstone is dark green chalcedony with red spots of iron oxide, rated about 6.5 to 7. Medieval Christian tradition linked the red spots to sacred legend. Both stones handle warm, soapy water well.

April: Diamond

Diamond is pure carbon arranged in a tight crystal structure, and it rates 10 on the Mohs scale. The word comes from the Greek adamas, meaning unconquerable, which inspired its traditional meaning of strength and lasting love. Diamonds attract grease, so regular cleaning with warm water, mild soap and a soft brush keeps them bright. Untreated diamonds usually tolerate ultrasonic cleaners, but fracture-filled diamonds do not.

May to August

May: Emerald

Emerald is green beryl colored by chromium, vanadium or both, with a hardness of about 7.5 to 8. Almost all emeralds contain internal features, and GIA notes that most are treated with oils or resins to make fractures less visible. That makes emerald more delicate than its hardness suggests. Clean it only with warm, soapy water, and avoid ultrasonic cleaners, steam, heat and solvents. Traditions link emerald with renewal and love.

June: Pearl, Moonstone and Alexandrite

Pearls are organic gems grown inside mollusks, made mostly of calcium carbonate layers called nacre. They are soft, about 2.5 to 4.5, and acids, perfume, hairspray and sweat can dull them. Jewelers often repeat the rule “last on, first off.” Wipe pearls with a soft, damp cloth after wearing and store them flat, away from harder jewelry.

Moonstone is a feldspar, rated about 6 to 6.5, prized for adularescence, the soft glow that seems to float across the surface. Like other feldspars, moonstone has cleavage planes that can split with a hard knock. See our moonstone guide for more.

Alexandrite is a rare color-change variety of chrysoberyl, about 8.5 in hardness. The stone appears green in daylight and red to purple in incandescent light. According to commonly repeated accounts, it was found in Russia’s Ural Mountains in the 1830s and named for the future Tsar Alexander II. Most alexandrite in jewelry today is lab-grown, which should be disclosed.

July: Ruby

Ruby is red corundum, colored by chromium, and rates 9. Only diamond is harder among common gems. Rubies have long been called the king of gems in Sanskrit and Indian traditions. Heat treatment is routine. Some lower-cost rubies are filled with lead glass, which can be damaged by household chemicals and jeweler’s heat, so ask about treatment before cleaning anything but warm, soapy water.

August: Peridot, Spinel and Sardonyx

Peridot is gem-quality olivine, rich in magnesium, rated about 6.5 to 7. GIA notes it is one of the few gems that comes in only one color, green, though shades vary. Ancient Egyptians mined it on the Red Sea island now called Zabargad. Avoid acids and sudden temperature changes. Our peridot guide covers its history in detail.

Spinel is magnesium aluminum oxide, rated about 8. Several famous “rubies” turned out to be red spinel, including the Black Prince’s Ruby in the British Imperial State Crown. Sardonyx is banded chalcedony with layers of brownish red sard, about 6.5 to 7, used for cameos since Roman times.

September to December

September: Sapphire

Sapphire is corundum in every color except red, most famously blue, and it rates 9. Traditions link it with wisdom and royalty. Heat treatment is common and stable. Like ruby, sapphire can be cleaned with warm, soapy water, while treated or filled stones need extra caution.

October: Opal and Tourmaline

Opal is a hydrated form of silica, meaning it contains water within its structure, and it rates about 5.5 to 6.5. Precious opal shows play-of-color, flashes of spectral color caused by tiny ordered spheres of silica. Heat, strong light and sudden temperature changes can cause fine cracks, a problem called crazing. Opal doublets and triplets, thin layers glued to a backing, should never be soaked. Wipe opal with a soft, damp cloth.

Tourmaline is a group of borosilicate minerals rated about 7 to 7.5. Tourmaline occurs in more colors than almost any other gem, with pink and green the most common October choices. Care is simple: warm, soapy water and a soft brush. Like black tourmaline, colored tourmaline can pick up a small electric charge when warmed and attract dust, so it may need wiping more often than other stones.

November: Topaz and Citrine

Topaz is an aluminum silicate containing fluorine, rated 8. Topaz has perfect cleavage, so a hard knock can split it. Blue topaz is usually created by irradiating and heating colorless topaz, a stable, accepted treatment. Avoid steam and ultrasonic cleaning. Citrine is yellow to orange quartz, rated 7, and much of it is heat-treated amethyst.

December: Turquoise, Zircon and Tanzanite

Turquoise is a copper aluminum phosphate, rated about 5 to 6. Being porous, turquoise can be stained by oils, lotions and cleaning products can stain it, and much turquoise is stabilized with resin. Clean it with a dry or barely damp cloth. Zircon is zirconium silicate, about 6 to 7.5, and is a natural mineral unrelated to the synthetic diamond simulant cubic zirconia. Tanzanite is blue-violet zoisite, rated about 6 to 7, known only from the Merelani Hills of northern Tanzania. Nearly all tanzanite is heat-treated to develop its color. Avoid ultrasonic and steam cleaning for both tanzanite and zircon.

Caring for Birthstone Jewelry

The safest general method for nearly every birthstone is the simplest: warm water, a few drops of mild dish soap, a soft toothbrush and a gentle rinse, followed by drying with a lint-free cloth. Pearls, opal and turquoise are the exceptions, and a soft damp cloth is the better choice for them.

Habits That Protect Every Stone

• Take rings off before gardening, cleaning, swimming and heavy lifting.
• Store pieces separately, because harder stones scratch softer ones.
• Keep perfume, lotion and hairspray away from pearls, opal, turquoise and emerald.
• Avoid ultrasonic and steam cleaners unless you know the stone is untreated and suited to them.
• Have prongs and settings checked by a jeweler once a year for rings worn daily.

Water-sensitive and soft stones need more caution in crystal practices too, such as moon-water rituals or leaving stones in a bowl of water overnight. Pearls, opal and turquoise should never be soaked, and stones with glued backings or resin treatments can loosen or cloud when wet. Our guide to which crystals cannot go in water lists more of them.

Buying Birthstones Honestly

Three words matter on any birthstone label: natural, treated and lab-grown. Lab-grown rubies, sapphires, spinels, emeralds and alexandrites have the same chemistry as natural stones and are a fair, lower-cost choice when disclosed. Simulants are different. Glass or cubic zirconia can imitate many birthstones but are not the same material.

The U.S. Federal Trade Commission’s Jewelry Guides say sellers should disclose treatments that significantly affect value or require special care, and should not call a lab-created stone simply a natural gem. Price is a useful clue. A large, bright, inexpensive “emerald” or “tanzanite” in a mall kiosk or an online marketplace listing is far more likely to be lab-grown or a simulant than natural. Asking a seller “Is this natural, treated or lab-created?” is the quickest way to learn what you are buying. For valuable pieces, a report from an independent gem lab gives the most reliable answer.

Frequently Asked Questions

What are the 12 birthstones in order?

January garnet, February amethyst, March aquamarine, April diamond, May emerald, June pearl, July ruby, August peridot, September sapphire, October opal, November topaz and December turquoise. Several months also have alternates, such as bloodstone, moonstone, alexandrite, spinel, tourmaline, citrine, zircon and tanzanite.

Who decides the official birthstones?

In the United States, the modern list comes from the 1912 National Association of Jewelers list, with later updates by industry groups such as the American Gem Trade Association and Jewelers of America.

Which birthstones are the most delicate?

Pearl, opal and turquoise are the softest and most sensitive. Emerald is hard but usually treated, so it also needs gentle care.

Can I use a different stone for my month?

Yes. Many people choose an alternate, a traditional or zodiac stone, or simply a favorite. Birthstones are a custom, not a rule.

Are lab-grown birthstones real?

Lab-grown stones have the same chemical and physical properties as natural ones. They must be disclosed as lab-grown, and they usually cost less.