Aquamarine Color Chart Explained: The Spectrum of Sea-Blue Beauty

I nearly bought the wrong aquamarine once.

It was at a gem show in Tucson, the kind of overwhelming sensory experience where every booth sparkles and every dealer claims to have the finest stones on earth. I was young, eager, and completely unprepared. A dealer placed a tray of aquamarines in front of me—dozens of them, ranging from nearly colorless to a deep, rich blue that made my breath catch.

“That one,” I said, pointing to the deepest blue. “I want that one.”

The dealer nodded, named a price that made my wallet flinch, and started writing up the sale. And I would have bought it, would have walked away with what I thought was the pinnacle of aquamarine quality, if not for the old jeweler at the next booth who leaned over and said, quietly:

“Ask him if it’s treated.”

I asked. The dealer hesitated. Then he admitted that the stone had been irradiated to achieve that deep, Maxixe-blue color—and that it would fade to pale gray within months of exposure to sunlight.

I didn’t buy that stone. And I learned, in that moment, that aquamarine color is not a simple ladder from “bad” to “good.” It is a landscape—complex, contested, and beautiful in ways that have nothing to do with intensity alone.

This article is the color chart I wish I’d had that day. It covers the geological origins of aquamarine’s color, the official grading systems and trade names, the controversial treatments, and the specific hues that collectors and jewelers actually value. By the end, you will never look at a blue beryl the same way again.

What Actually Makes Aquamarine Blue?

Let’s start at the atomic level, because the color of aquamarine is not a surface application or a trick of light. It is written into its crystal structure.

Aquamarine is a variety of beryl, chemical formula Be₃Al₂Si₆O₁₈ . The same mineral, in different chemical states, gives us emerald (green), morganite (pink), heliodor (yellow), and goshenite (colorless). The difference between these gemstones is measured in parts per million of specific trace elements.

Aquamarine’s blue comes from iron.

Specifically, the presence of ferrous iron—Fe²⁺—within the beryl crystal lattice absorbs yellow and red wavelengths of light, transmitting the blue and green wavelengths we perceive as aquamarine. The more iron, generally, the more intense the color. But it is not that simple. The oxidation state of the iron, its position within the crystal structure, and the presence of other trace elements all influence the final hue.

This is why aquamarine can range from the palest, almost-invisible ice blue to a deep, saturated Santa Maria blue. It is not a single color but a family of colors, united by their origin in the same mineral but separated by the specific geological conditions of their formation.

The hexagonal crystals grow slowly over millions of years in granite pegmatites and hydrothermal veins . As they grow, they incorporate iron from the surrounding environment. The temperature, pressure, and chemical composition of that environment determine how much iron is included, and in what form. Two aquamarines from the same mine, found within meters of each other, can have noticeably different colors.

This is the first and most important fact about aquamarine color: it is natural, variable, and inherently unique to each crystal. No two are exactly alike.

The Spectrum—From Ice to Ink

If you laid every possible aquamarine color in a single gradient, it would span from the palest, almost-transparent blue at one end to a deep, ink-like blue at the other, with a significant stop in between for the classic greenish-blue tones that give the stone its name.

The palest grades hover at the edge of perception. These stones are sometimes called “ice” aquamarines or “white” aquamarines, though neither term is official. They are nearly colorless, with just a whisper of blue. They are also the most affordable, and when cut well, they have a clean, minimalist beauty that appeals to contemporary tastes.

The classic aquamarine is the color of seawater in the tropics—that specific blue with a distinct green component. This is the color that gave the stone its name, and it remains enormously popular. It is not “lesser” than deeper blue; it is historically authentic and undeniably beautiful.

The deep blues are what most collectors and jewelers prize above all else. These stones have minimal green modifiers and a saturation that approaches the intensity of fine blue topaz or even light sapphire. The most famous of these deep blues is Santa Maria, named after the Brazilian mine that produced them.

The Maxixe variety is the outlier. Named after the Maxixe mine in Minas Gerais, these stones display a deep, inky blue that is far more intense than even the finest Santa Maria. However, nearly all Maxixe-color aquamarine is either naturally unstable (fading rapidly in light) or artificially induced through irradiation . Natural, stable Maxixe is extraordinarily rare and valuable. Irradiated Maxixe is a controversial product that many collectors avoid.

The spectrum is continuous. There is no single “correct” aquamarine color. But there are grades, standards, and trade names that help us navigate the continuum.

The Commercial Grading Scale (A Through Gem)

For decades, the aquamarine trade has operated on a letter-grade system that every buyer should understand. It is not standardized by any official gemological body—the Gemological Institute of America does not certify this scale—but it is universally used by dealers, cutters, and wholesalers .

GEM Grade (sometimes AAAA):
This is the top tier. GEM-grade aquamarine possesses a pure blue or very slightly greenish-blue hue with a light to medium-light tone and strong to vivid saturation. The color must be evenly distributed, and the stone must be eye-clean—no visible inclusions. These stones represent approximately the top 10% of all aquamarine production .

AAA Grade:
Virtually identical to GEM grade in clarity and overall quality, but with slightly weaker depth of color. The difference between GEM and AAA is subtle; a AAA stone placed next to a GEM stone will appear marginally less saturated. Both grades command premium prices, often several hundred dollars per carat .

AA Grade:
Here we see a noticeable drop in quality. AA-grade stones have paler body color, usually with more pronounced secondary shades of green or gray. Clarity may also decrease, with inclusions visible to the naked eye. The price per carat drops significantly at this level .

A Grade:
Commercial quality. These stones are clearly aquamarine but lack the intensity and purity of higher grades. They may appear washed out or heavily greenish. They are suitable for affordable jewelry and are by far the most common on the mass market.

B and C Grades:
These grades are rarely sold as faceted gemstones. They are typically opaque, heavily included, or so pale as to be almost colorless. They may be used for carving, cabochons, or sold as rough to hobbyists.

Important note: This grading scale applies to color only within the context of overall quality. A stone can have GEM color but be disqualified from the grade due to poor clarity, poor cut, or excessive treatment. Conversely, a stone with slightly weaker color but flawless clarity and perfect cutting may be priced higher than a GEM-grade stone with visible inclusions.

The Santa Maria Revolution—A New Standard

In 2022, something unprecedented happened in the aquamarine world. The Asian Institute of Gemological Sciences—AIGS, one of the most respected gemological laboratories in the world—codified a formal standard for the trade name “Santa Maria” .

This matters because trade names for gemstone colors have historically been subjective. “Pigeon blood” ruby, “royal blue” sapphire, “Santa Maria” aquamarine—these terms were evocative but imprecise. One dealer’s Santa Maria was another dealer’s merely dark blue. Buyers had no objective reference.

AIGS changed that.

The Santa Maria standard specifies:

• Blue hue with medium to high saturation
• No brown or yellow secondary tones
• Minimum saturation threshold established by physical master stones
• Applicable to any aquamarine regardless of geographic origin

This last point is crucial. “Santa Maria” originally referred specifically to aquamarines from the Santa Maria de Itabira mine in Minas Gerais, Brazil—a source now almost completely depleted . Under the new AIGS standard, an aquamarine from Mozambique, Nigeria, or Madagascar can be certified as Santa Maria if it meets the color criteria .

The industry has largely embraced this standardization. Kennedy Ho, chairman of AIGS, explained the rationale: “Trade names such as pigeon blood and royal blue have been used for centuries by gem traders to describe ideal colors implying value and rarity. Yet these trade names are often ambiguous with definitions varying between buyers and sellers alike. By transforming trade names into an industry standard through reports graded by third-party objectivity, AIGS aims to reduce such ambiguity” .

Santa Maria Africana is a related but distinct term. It emerged organically in the trade to describe high-quality deep-blue aquamarines from Mozambique that rivaled the original Brazilian material . While not officially codified, the term persists and signals a stone of exceptional color from African sources.

The Green Question—When Blue Isn’t Pure

Here is a source of endless confusion for aquamarine buyers.

Aquamarine, by definition, is blue to greenish-blue. The green component is not a flaw; it is part of the stone’s natural color range. The name itself—”seawater”—acknowledges this aquatic blend.

Yet the market has spoken, and the market prefers blue. Pure blue commands higher prices than greenish-blue. This is a matter of fashion, not quality. A fine greenish-blue aquamarine from the 19th century, perfectly preserved in its original setting, is not inferior to a contemporary blue stone. It is simply less aligned with current taste.

The AIGS Santa Maria standard explicitly excludes stones with yellow and brown tones, but it does not explicitly exclude green tones. The language specifies “blue color” with “medium saturation without brown or yellow tints” . Green is not mentioned as a disqualifier, though in practice the Santa Maria masters skew toward pure blue.

The green spectrum itself varies:

• Aqua-green: The classic seawater color. Blue with distinct green modifiers. Historically authentic.
• Green-blue: More green than blue. These stones are less expensive and often sold as “aquamarine” but may be labeled more specifically by honest dealers.
• Yellow-green: Rare and generally undesirable in the aquamarine trade. Stones with pronounced yellow modifiers are often heat-treated to reduce the yellow component.

The Smithsonian’s National Museum of Natural History describes the ideal aquamarine as exhibiting “the color of the sea: rich blue to greenish-blue. Deep blue is the most highly prized color” . Note the inclusion of greenish-blue as legitimate, even desirable. The museum’s collection includes both pure blue and greenish-blue specimens, each beautiful in its own way.

Heat Treatment—The Invisible Intervention

Here is the uncomfortable truth about aquamarine color: most of it has been altered.

Heat treatment of aquamarine is widespread, accepted, and—crucially—nearly impossible to detect without advanced laboratory equipment. The process is simple: stones are heated to approximately 400-450 degrees Celsius, which reduces the yellow and green components caused by ferric iron, enhancing the blue color .

This treatment is permanent and stable under normal conditions. A heat-treated aquamarine will not fade or change color over decades of normal wear. It is not considered deceptive by the gemological establishment, provided it is disclosed. The vast majority of commercial aquamarine on the market today has undergone some form of heat treatment.

However.

There is a significant distinction between standard heat treatment and irradiation treatment.

Standard heat treatment simply removes unwanted color components. It does not add color that wasn’t naturally present in the stone; it reveals the blue that was already there beneath the yellow modifiers. This is analogous to the heat treatment universally applied to sapphires and rubies.

Irradiation treatment creates color that did not exist naturally. When colorless or pale beryl is exposed to gamma rays, neutrons, or X-rays, it can develop a deep Maxixe-blue color . This color is often unstable and may fade rapidly when exposed to light. Some irradiated stones are subsequently heat-treated to stabilize the color, but the treatment is still fundamentally different from simple heat enhancement.

The International Gem Society notes: “Naturally occurring blue hued aquamarine specimens are more expensive than those that have undergone heat treatment to reduce yellow tones caused by ferric iron” . The key word is “naturally occurring.” Heat-treated stones are less valuable than untreated stones of equivalent apparent color—but they are far more affordable and constitute the vast majority of the market.

How can you know?

Ask for disclosure. Reputable dealers will tell you whether a stone has been treated and what kind of treatment it has received. If a dealer claims a stone is “untreated,” request laboratory documentation. Fine untreated aquamarines exist—they are simply rare and priced accordingly.

The Problem with Maxixe

Maxixe aquamarine deserves its own section because it is the source of more confusion and disappointment than any other aquamarine variety.

The Maxixe mine in Minas Gerais, Brazil, produced beryl with an unusually deep blue color caused by color centers associated with nitrate ions (NO₃) rather than iron . These stones were stunning—a deep, saturated blue that surpassed even the finest Santa Maria.

But they faded.

Exposure to sunlight caused the color to degrade, sometimes within hours, always within months. The deep blue would bleach to a pale, unappealing gray. Collectors who paid premium prices for Maxixe stones found themselves holding worthless material.

Later, scientists discovered that this deep blue color could be artificially induced in otherwise pale beryl through irradiation . This created a flood of “Maxixe-blue” aquamarine on the market—some of it disclosed, much of it not. The irradiated color is often more stable than the natural Maxixe color, but it is still subject to fading and is universally considered less valuable than natural color.

The practical advice:

If you encounter an aquamarine with a blue so deep it approaches the color of fine sapphire or tanzanite, proceed with extreme caution. Genuine, untreated, color-stable aquamarine of this intensity is extraordinarily rare and commands prices that reflect that rarity. If the price seems too good to be true for such a deep blue stone, it is almost certainly treated or irradiated—and possibly unstable.

The Visual Color Chart (What You’re Actually Seeing)

Let me translate the technical grades and trade names into something you can actually use when you’re looking at stones.

Ice / White Aquamarine:

• Appearance: Nearly colorless, faintest blue whisper
• Commercial Grade: A to B
• Price: Very affordable
• Best For: Minimalist jewelry, stackable rings, buyers who prefer subtlety
• Note: Often confused with goshenite (colorless beryl); look for the faintest blue tint

Pale Aquamarine:

• Appearance: Clearly blue, but light and delicate
• Commercial Grade: AA to A
• Price: Moderate
• Best For: Everyday earrings, pendants, delicate rings
• Note: The most common grade in commercial jewelry

Classic Aquamarine:

• Appearance: Seawater blue, noticeable green component
• Commercial Grade: AAA to AA
• Price: Moderate to high
• Best For: Traditionalists, March birthdays, those who love the stone’s namesake color
• Note: Historically authentic; undervalued in current market

Santa Maria:

• Appearance: Pure blue, minimal to no green, medium-dark tone
• Commercial Grade: GEM to AAA
• Price: High to very high
• Best For: Collectors, investment-grade purchases, engagement rings
• Note: AIGS certification available; original Brazilian material extremely rare

Santa Maria Africana:

• Appearance: Deep blue, comparable to Santa Maria
• Commercial Grade: GEM to AAA
• Price: High
• Best For: Buyers seeking Santa Maria quality at slightly lower prices
• Note: Mozambique origin; increasingly recognized as equal to Brazilian

Maxixe-Blue:

• Appearance: Ink-blue, extremely deep and saturated
• Commercial Grade: Not applicable (color instability)
• Price: Variable; generally lower than stable blues
• Best For: Collectors who understand the stability risks; not recommended for daily wear
• Note: Require full disclosure; avoid if not certified as color-stable

Blue-Green:

• Appearance: More green than blue
• Commercial Grade: AA to A
• Price: Low to moderate
• Best For: Fashion jewelry, those who prefer green tones
• Note: Often heat-treated to reduce green; untreated specimens increasingly rare

Color Versus the Other Cs

A dangerous misconception among new buyers is that color is the only factor that matters. It is not.

A GEM-grade color stone with poor cutting, visible inclusions, or excessively dark tone will be worth less than a AAA-grade stone with excellent cutting, flawless clarity, and ideal light transmission. The Four Cs work together; no single factor determines value in isolation.

Tone and saturation are as important as hue. A stone with perfect blue hue but excessively dark tone will appear almost black in certain lighting. A stone with perfect saturation but uneven distribution will have patches of pale and intense color. AIGS’s Santa Maria standard explicitly requires “medium saturation”—not maximum saturation .

Pleochroism is a factor in aquamarine that many buyers overlook. Aquamarine is pleochroic, meaning it displays different colors when viewed from different crystallographic directions. Typically, aquamarine appears darker blue when viewed along the length of the crystal and paler, more greenish when viewed across it. A skilled cutter orients the stone to maximize desirable color through the table .

Clarity is particularly important in aquamarine because the stone is valued for its clean, transparent appearance. Unlike emerald, where inclusions are expected and even valued as “jardin,” aquamarine is expected to be eye-clean at minimum. Heavily included aquamarine is rarely faceted; it is usually cut as cabochons or carved .

Cut quality affects color perception dramatically. A well-cut aquamarine with proper proportions will reflect light internally, bouncing it back through the table and creating the illusion of deeper, richer color. A poorly cut stone will leak light through the pavilion, appearing paler and less saturated than its actual body color.

The Emotional Color Chart (What the Colors Mean)

I have spent years watching customers gravitate toward specific aquamarine colors, and I have come to believe that our preferences are not random. The color we choose reflects something about who we are and what we need from the stone.

The palest aquamarine is chosen by minimalists, by those who prefer whisper to shout, by people who want their jewelry to be discovered rather than announced. It is the color of early morning light on a calm sea, and it attracts those who value subtlety and restraint.

The classic seawater aquamarine is chosen by traditionalists, by March babies who want the stone their grandmother would recognize, by romantics who love the name and the mythology. It is the color of the Mediterranean in summer postcards, and it attracts those who value authenticity over trend.

The Santa Maria blue is chosen by collectors, by those who want the finest and are willing to pay for it, by people who study before they buy. It is the color of deep Caribbean waters, and it attracts those who value excellence and rarity.

The blue-green aquamarine is chosen by individualists, by those who know the market prefers pure blue and deliberately choose otherwise. It is the color of tide pools and northern seas, and it attracts those who trust their own eye over conventional wisdom.

None of these choices is wrong. The emotional color chart is the only one without hierarchy.

How to Buy Aquamarine Color (A Practical Guide)

You have read the grades, the trade names, the treatment disclosures. Now, here is how to actually apply this knowledge when you are standing at a counter, holding a stone in your hand.

Step One: Establish your budget.

Aquamarine is more affordable than ruby, sapphire, or emerald, but fine-quality stones are not cheap. GEM and AAA grades cost several hundred dollars per carat and up . AA and A grades are significantly less expensive. Know your range before you fall in love.

Step Two: Decide on your color priority.

Do you want pure blue at any cost? Or are you open to the classic greenish-blue? Are you buying for investment (prioritize untreated Santa Maria with certification) or for personal adornment (prioritize whatever makes you happy)?

Step Three: Ask the questions.

• Is this stone heat-treated? (Assume yes unless documented otherwise.)
• Is this stone irradiated? (If the blue is extraordinarily deep, ask specifically.)
• Does it have any color stability issues? (Relevant only for Maxixe-type stones.)
• What is the origin, if known? (Brazilian Santa Maria commands premium; Mozambique Santa Maria Africana is comparable; other sources are valued on individual merit.)
• Is the color evenly distributed? (View the stone from multiple angles.)

Step Four: Look at the stone in multiple lights.

Aquamarine color shifts under different lighting conditions. View the stone in daylight, under incandescent light, and under fluorescent store lighting. A stone that looks deep blue under jewelry store spots may appear pale in natural light. This is not necessarily a flaw—all aquamarine does this to some degree—but you should know what you’re buying.

Step Five: Compare side by side.

If possible, place the stone next to others of similar quality. Color is relative; a stone that seemed beautifully saturated in isolation may appear pale next to a GEM-grade stone. Conversely, a stone that seemed adequately blue may suddenly appear greenish. This comparison is the most effective way to calibrate your eye.

Step Six: Trust yourself.

The technical information in this article is designed to inform your decision, not override it. If you fall in love with a pale greenish-blue aquamarine that every collector would dismiss, buy it. It is your stone. Your affection for it is the only valuation that ultimately matters.

The Future of Aquamarine Color

The Santa Maria standard is only the beginning. AIGS has signaled its intention to continue standardizing color terminology across the gemstone industry, following its successful codification of “Jedi spinel” . We can expect more objective, laboratory-verified color grades for aquamarine in the coming years.

Simultaneously, the original Santa Maria de Itabira mine remains depleted. Brazilian Santa Maria aquamarine will only become rarer and more expensive. Mozambique has emerged as the dominant source of fine deep-blue aquamarine, and the “Santa Maria Africana” designation—once a marketing distinction—is now a legitimate quality indicator .

Treatment technology continues to advance. Current heat treatment is stable and detectable only with advanced equipment. Future treatments may be even more sophisticated, further blurring the line between natural and enhanced color.

And yet, despite all this standardization and technology, aquamarine remains what it has always been: a crystal of beryl, colored by trace amounts of iron, formed over millions of years in the cooling depths of the Earth. No laboratory can replicate that timescale. No grading standard can capture the experience of holding a perfect blue crystal in your palm and seeing the sea inside it.

The Color Chart You Carry in Your Heart

I never bought that irradiated Maxixe stone in Tucson. I walked away from the booth, my wallet intact and my education begun.

A few years later, I found my aquamarine. It is not Santa Maria grade. It is not even AAA. It is a classic seawater blue—distinctly greenish, medium-light in tone, with a small inclusion visible under magnification. It cost me less than a nice dinner.

I wear it almost every day. When the light catches it just right, I see not the color on the AIGS master scale or the GEM-grade standard or the heat-treatment disclosure. I see the ocean I grew up next to. I see the name my grandmother loved. I see the stone I chose, not the stone an algorithm or a grading report told me to want.

The color chart explained in this article will help you navigate the aquamarine market with confidence. It will protect you from overpaying, from misrepresentation, from the disappointment of unstable color. It will teach you the language that jewelers and collectors speak.

But the color chart you carry in your heart—that is the one that will lead you to your stone.

Pay attention to both.

Ready to find your perfect aquamarine? Browse our collection below, organized by color grade and treatment disclosure. Every stone is accompanied by our honest assessment of its color quality, origin information where known, and clear treatment disclosure. No ambiguity. No surprises. Just the color of the sea, captured in beryl.

[Shop GEM-Grade Aquamarine]
[Shop AAA Aquamarine]
[Shop Classic Seawater Aquamarine]
[Shop Certified Santa Maria Aquamarine]