If you were born in March, you get the sea. Aquamarine, the modern March birthstone, takes its name from the Latin for "water of the sea," and the best of them look exactly like that: clear, cool blue with the faintest breath of green, like shallow water over white sand. March also has a traditional birthstone, bloodstone, an opaque dark green gem flecked with red that could hardly be more different. This guide explains both, with most of the attention on aquamarine, since that is the stone most people are shopping for, and on the details that separate a lovely aquamarine from a forgettable one.
The Two March Birthstones at a Glance
Aquamarine is a transparent blue to greenish blue variety of beryl, the same mineral species as emerald. It is typically faceted, typically very clean and, at 7.5 to 8 on the Mohs scale, well suited to rings worn every day. Bloodstone, also called heliotrope, is a variety of chalcedony, a microcrystalline quartz. It is opaque, deep green, spotted with red iron oxide, and usually cut as cabochons, beads, carvings and signet-ring tablets. If you want sparkle and color, choose aquamarine. If you want something earthy, old-world and a little mysterious, bloodstone is your stone.
What Gives Aquamarine Its Color
Aquamarine owes its color to trace iron in the beryl crystal. Iron in one state produces blue; iron in another adds a yellow component, and together they read as the greenish blue that most rough shows out of the ground. That is also why aquamarine and emerald, both beryl, look nothing alike: emerald's green comes from chromium and vanadium instead. You can read more about the whole family on our aquamarine education page and our overview of gemstone types.
Two practical consequences follow. First, color in aquamarine is almost always light to medium in tone. A deep, saturated blue is the exception, and it commands a real premium. Second, aquamarine is noticeably pleochroic: viewed along one direction of the crystal it looks blue, and along another it looks nearly colorless. A skilled cutter orients the rough so that the table faces the blue direction. A poorly oriented stone can look washed out even when the rough had good color.
Why Bigger Aquamarines Look Bluer
Aquamarine's color is gentle enough that the path length of light through the stone makes a visible difference. A small stone of the same material will look paler than a large one, simply because light travels a shorter distance through it before returning to your eye. This is why a truly blue look is easier to find in larger sizes, and why small melee aquamarines tend to read as pale ice blue. It is worth keeping in mind if you are choosing a small stone for a stacking ring or a pair of studs.
How to Judge Aquamarine Color
Color drives value in aquamarine far more than anything else. Using the three dimensions we cover in our guide to hue, tone and saturation, here is how the trade tends to think about it:
- Hue: Pure to slightly greenish blue is the classic target. A stronger green component is attractive in its own right and has its fans, but it is generally valued below a clean blue.
- Tone: Medium is the sweet spot. Very light stones can look glassy; stones that are too dark are rare in aquamarine and seldom a problem.
- Saturation: The more vivid, the better. A gray or washed-out quality lowers value, while a lively, saturated blue is what collectors hunt for.
Look at any aquamarine in more than one light. Daylight and neutral LED tend to flatter it; warm incandescent light can pull a stone slightly greener. If a seller only shows you one photograph under one light, ask for another.
Santa Maria and Other Trade Names
You may see the term "Santa Maria" used for aquamarines of unusually deep, saturated blue. It originally referred to material from the Santa Maria de Itabira mine in Minas Gerais, Brazil, and was later borrowed for similar material from Africa, sometimes as "Santa Maria Africana." Today it is best understood as a color description used in the market rather than a guarantee of origin. If origin matters to you, it should be supported by the seller's documentation, not by a trade name alone. Our guide to gemstone origin covers why.
Is Aquamarine Heated?
Very often, yes. Much aquamarine rough comes out of the ground with a greenish or yellowish cast, and gentle heating removes that yellow component to leave a purer blue. The result is stable, permanent and not something you need to worry about in wear. It is also usually not detectable, which is why the market broadly assumes that blue aquamarine may have been heated and prices it accordingly. Unheated stones exist, but unlike sapphire, "no heat" does not carry a large premium in aquamarine. We state a stone's treatment wherever it is known, and our article on gemstone treatments puts heat in context alongside the treatments that do matter.
The one aquamarine look-alike worth knowing by name is Maxixe-type beryl: beryl turned an intense, almost inky blue by irradiation. Its color fades on exposure to light, sometimes within days. It is uncommon in the market, but a surprisingly dark blue "aquamarine" at an unusually attractive price is exactly the situation where a lab report earns its keep.
Clarity: Aquamarine Should Look Clean
Beryl can grow as large, remarkably clean crystals, so faceted aquamarine is expected to be eye-clean. That is a very different standard from its sibling emerald, whose garden of inclusions is accepted and even loved. When inclusions are present in aquamarine, they are often fine parallel tubes (sometimes called rain), small fluid inclusions, or feathers. Under magnification these are normal. To the unaided eye, though, a visible inclusion in a mid-size aquamarine is a genuine reason to keep looking or to expect a lower price. Our clarity guide explains how expectations shift from one species to the next.
Cut, Shape and Size
Because aquamarine's color is delicate, cut matters more than people expect. A well-proportioned stone returns light evenly across the face; a shallow one shows a washed-out window in the center, and an overly deep one can look dark at the edges and pale in the middle. Emerald cuts are a classic choice because their long step facets show off the stone's clarity like a pane of seawater, while brilliant-style ovals, cushions and pears add more sparkle and can make a lighter stone look livelier. Pears and hearts are especially lovely in pendants.
Aquamarine is also relatively light for its size. Its specific gravity is well below sapphire's, so a one-carat aquamarine looks noticeably larger face-up than a one-carat sapphire of the same shape. If you are planning a setting, buy by millimeter dimensions rather than by carat weight; our guide to carat weight versus visual size walks through why.
Durability and Everyday Wear
At 7.5 to 8 on the Mohs scale, aquamarine is hard enough for engagement rings and daily-wear pieces, and it has no cleavage problem to speak of. Its color does not fade in light. As with any fine gem, avoid sudden temperature changes and hard knocks, and clean it with warm water, mild soap and a soft brush. Our guide to gemstone durability and care covers the details.
Bloodstone is softer, at roughly 6.5 to 7, and as a polished cabochon it is best suited to pendants, cufflinks and signet rings that see gentler wear. Keep it away from harsh cleaners and ultrasonic machines.
How to Spot Aquamarine Imitations
The most common stand-in is blue topaz, which is typically irradiated and heated to a stronger, more electric blue than most aquamarine. Topaz is heavier and has a higher refractive index, so a gem lab separates them quickly; to the eye, a vivid "Swiss" or "London" blue is a strong hint you are looking at topaz. Synthetic spinel and glass also appear in inexpensive jewelry. Synthetic aquamarine can be grown hydrothermally, but it is rarely encountered. For a significant purchase, ask for a lab report and read it carefully; our guide to reading a gem lab report will help.
Bloodstone: March's Traditional Birthstone
Bloodstone is dark green chalcedony dotted with red to reddish-brown spots of iron oxide. It has been carved and worn since antiquity, prized for seals and intaglios because it takes a crisp polish and holds fine detail. Look for an even, deep green body with well-distributed red spots; too much brownish jasper-like matrix reduces its appeal. Because it is opaque, clarity grading does not apply in the way it does to aquamarine. Good bloodstone has a clean, glassy polish without pits.
Aquamarine in the Wider Story
Aquamarine has long been associated with calm, clarity and the sea, and it was carried by sailors as a talisman for safe passage. It is also a traditional gift for a 19th wedding anniversary, as we note in our anniversary gemstones guide. The most famous aquamarine in the world may be the Dom Pedro, a monumental Brazilian aquamarine of more than 10,000 carats carved by Bernd Munsteiner and now in the Smithsonian's National Gem Collection.
Buying a March Birthstone with Confidence
- Prioritize color: clean blue to slightly greenish blue, medium tone, lively saturation.
- Expect an eye-clean stone, and question visible inclusions.
- Check the face-up appearance for windows or dark edges.
- Assume heat is possible, and treat unusually dark blue at a low price with caution.
- Buy by millimeter size for a setting, and view the stone in more than one light.
You can browse our current aquamarines for live pricing and availability. Every listing states whether a stone is natural, lab-grown or cultured. If you have a design in mind, our bespoke jewelry service can build fine jewelry around your March birthstone, and if you are looking for a particular size or shade, a sourcing request is the easiest place to start.
Frequently Asked Questions
What is the birthstone for March?
March has two birthstones. Aquamarine is the modern March birthstone, a transparent blue to greenish blue variety of beryl that is usually faceted and very clean. Bloodstone is the traditional March birthstone, an opaque dark green chalcedony spotted with red iron oxide, usually cut as cabochons, beads or signet-ring tablets. Most people shopping for March birthstone jewelry today choose aquamarine for its color, sparkle and durability, while bloodstone appeals to those who love an earthy, antique look. Either is a meaningful choice for a March birthday.
What color aquamarine is the most valuable?
The most valued aquamarines show a clean blue to slightly greenish blue hue, a medium tone and strong, lively saturation. Very pale stones and stones with a gray or washed-out look are valued lower, and a strong green component is attractive but generally priced below a purer blue. Deep, saturated blue is rare in aquamarine and commands a premium, sometimes described in the market with the trade name Santa Maria. Color also deepens with size, so larger stones tend to show more blue. For live pricing, browse our aquamarine collection.
Are aquamarines heat treated?
Many are. Aquamarine rough often has a greenish or yellowish cast, and gentle heating removes the yellow component to leave a purer blue. The result is stable and permanent, and it is usually not detectable, so the market broadly assumes blue aquamarine may have been heated. Unlike sapphire, an unheated aquamarine does not usually carry a large premium. The treatment to watch for is Maxixe-type beryl, an irradiated deep blue beryl whose color fades in light. We state a stone's treatment wherever it is known.
Is aquamarine durable enough for an everyday ring?
Yes. Aquamarine is 7.5 to 8 on the Mohs scale, which makes it hard enough for engagement rings and other pieces worn daily. Its color does not fade in light, and it is expected to be clean, with few inclusions that could weaken the stone. As with any fine gem, avoid hard knocks and sudden temperature changes, and clean it with warm water, mild soap and a soft brush. Bloodstone is softer at roughly 6.5 to 7 and is better suited to pendants, cufflinks and signet rings that see gentler wear.
How can I tell aquamarine from blue topaz?
Blue topaz is the most common aquamarine look-alike. It is usually treated to a stronger, more electric blue than most aquamarine, so a vivid Swiss or London blue is a strong hint you are looking at topaz. Aquamarine tends toward a softer, slightly greenish blue. The two are separated reliably with gem testing, because topaz is heavier and has a higher refractive index. Synthetic spinel and glass also appear in inexpensive jewelry. For a significant purchase, ask for a lab report and read it carefully before you buy.
Why does a small aquamarine look paler than a large one?
Aquamarine's color is gentle, so the distance light travels through the stone makes a visible difference. In a small stone, light passes through less material before returning to your eye, so the same rough reads paler than it would in a larger stone. That is why vivid blue is easier to find in bigger aquamarines, and why small accent stones often look ice blue. Cut matters too: a well-oriented, well-proportioned stone shows its best color face-up. When choosing for a setting, compare stones by millimeter size rather than carat weight.
