Why has my Aquamarine faded?
Somewhere in the world right now, someone is opening a jewellery box to find that the deeply saturated blue stone they bought a year ago now looks pale, greenish, or oddly brownish. If the stone was sold as aquamarine and the price seemed suspiciously good for such a rich colour, there is a reasonable chance the customer was actually sold Maxixe beryl. Here is what that means, why it happened, and how to avoid it.
What is Maxixe beryl?
Maxixe (pronounced ma-SHE-she) is a deep blue to violet-blue variety of beryl first discovered in 1917 at the Maxixe mine in Minas Gerais, Brazil. Its saturated blue can appear richer than the finest aquamarine, and that is precisely the problem. Unlike aquamarine, whose blue is stable and permanent, Maxixe owes its colour to unstable colour centres that fade on exposure to light or heat.
Maxixe is not the same stone as aquamarine, even though both are chemically beryl. The difference lies in the source of colour, the stability of that colour, and the commercial category the stone belongs in.
How does Maxixe get its colour?
Aquamarine is coloured by iron trapped in the beryl crystal structure. This is a stable coloration that will not fade under normal wear.
Maxixe is different. According to research published in Gems & Gemology (Adamo et al., 2008), Maxixe beryl is characterised by an iron-free chemical composition. Its colour comes from irradiation-induced colour centres in nitrate or carbonate impurities within the crystal channels, not from iron.
The irradiation can occur naturally in the ground or be induced artificially in a laboratory. Colourless goshenite, pale morganite, and even pale aquamarine can all be turned a rich blue by artificial irradiation, producing what the trade often calls "Maxixe-type" beryl. Per the GIA laboratory, there is no conclusive test to determine whether Maxixe colour results from natural or artificial irradiation, and stones displaying the characteristic spectrum are designated simply as the Maxixe variety of beryl regardless of origin.
Why does Maxixe fade?
Maxixe fades rapidly when exposed to sunlight or temperatures above 100°C, losing its blue and shifting toward yellowish or brownish tones. The fading occurs because the irradiation-induced colour centres break down under light and heat. The same energy that displaced electrons to create the colour eventually allows them to return, undoing the blue.
The rate of fading varies. In direct sunlight, visible fading can occur in a matter of hours. In more typical wear conditions, indoors much of the time but with regular sun exposure, a Maxixe stone may hold its colour for weeks or months before noticeable degradation. The end state is the same: a once-vivid blue stone reduced to a pale, brownish, or yellow shadow of its original self.
The colour can be restored by re-irradiation and annealing, but the restoration is not permanent. A Maxixe stone that has been re-treated will fade again with continued exposure. There is no known way to stabilise the colour.
What does this mean for buyers and customers?
For a wholesale buyer, Maxixe presents a specific commercial risk. A stone sold as "aquamarine" that is in fact Maxixe will lose its colour in a customer's jewellery box or on their hand within weeks to months of normal wear, depending on light exposure. The customer who paid for a saturated blue stone will return with a pale, brownish, or yellow one, and the retailer will bear the reputational cost regardless of where the stone originated in the supply chain.
Maxixe itself does have a legitimate market as a collector's curiosity. Its saturation can exceed the finest aquamarine, and specimens stored away from light retain their colour indefinitely. But it belongs in a display case or vault, not in a ring or pendant intended for daily wear. Any Maxixe sale should be accompanied by explicit disclosure of the fading behaviour and appropriate storage guidance.
The customer expectation issue is particularly acute because Maxixe is so visually appealing. A buyer inexperienced with beryl varieties may see a stone offered as "premium aquamarine" at what appears to be a competitive price and reasonably conclude they have found a bargain. The truth only reveals itself later, when the stone has faded and the transaction cannot easily be reversed.
How can Maxixe be differentiated from aquamarine?
Several diagnostic features separate Maxixe from aquamarine, in ascending order of certainty:
Colour saturation
Maxixe often shows a deeper, more saturated blue than aquamarine typically achieves, sometimes with a violet component. A blue beryl that appears richer than the finest Santa Maria aquamarine warrants scrutiny. This is not a definitive test on its own but a useful starting flag.
Reversed pleochroism
This is the classical gemological test and does not require laboratory equipment. In Maxixe, the strongest blue is seen down the c-axis of the crystal, with weaker blue perpendicular to it. In aquamarine, the pleochroism is reversed. The strongest blue is perpendicular to the c-axis. A dichroscope reveals this difference immediately in the hands of a trained gemmologist. For a working trade professional, this is the single most useful field test.
Longwave UV response (with important caveats)
A common question is whether standard longwave UV (LWUV) testing can distinguish Maxixe from aquamarine. The honest answer is that LWUV alone is only weakly diagnostic.
The theory is that aquamarine is typically inert to UV, whereas Maxixe can fluoresce green. In practice, many Maxixe stones show weak or no LWUV response at all. The greenish fluorescence, when present, appears more reliably under shortwave UV (SWUV) than longwave. The GIA published a case study in 2020 on an unusual violet Maxixe that was inert to longwave UV and only showed a weak greenish-yellow reaction under shortwave.
So the practical interpretation is:
- A positive LWUV result (green fluorescence in a deeply saturated blue beryl) is a genuine red flag worth taking seriously.
- A negative LWUV result rules out very little. Plenty of confirmed Maxixe stones are inert to longwave.
- SWUV is more informative than LWUV for this specific separation, but requires a shortwave lamp that is less commonly kept on a jeweller's bench.
Use LWUV as a supplementary indicator, not a standalone test.
UV-Vis-NIR spectroscopy
This is the definitive identification method used by laboratories. Maxixe shows a distinctive absorption spectrum with a prominent narrow peak at approximately 691 nm and smaller peaks at roughly 646, 630, 607, and 590 nm (Adamo et al., 2008). Aquamarine, by contrast, shows iron-related absorption bands at approximately 370 and 427 nm along with a broad band centred near 825 nm. The two spectra are unmistakably different. Any deeply saturated blue beryl offered at an aquamarine price warrants a UV-Vis-NIR test at a reputable laboratory before purchase.
Iron content analysis
Elemental analysis by LA-ICP-MS will show Maxixe to be effectively iron-free, while aquamarine will show measurable iron content. This is a laboratory-only test but is definitive.
Fade testing
A simple confirmation for material already suspected: controlled exposure to strong sunlight or gentle heat over hours to days will cause Maxixe to fade visibly, while aquamarine remains unchanged. This is destructive to the Maxixe stone's colour and should only be performed on a small trial parcel with disclosure and consent. Some experienced buyers use fade testing as a routine practice when offered suspiciously saturated blue beryl from unfamiliar sources.
What to do when offered suspiciously saturated blue beryl
For any deeply saturated blue beryl offered without laboratory documentation, the professional response is straightforward. Request a lab report running UV-Vis-NIR spectroscopy before purchasing at aquamarine prices.
For inventory that has already been purchased and is under suspicion, the dichroscope test is the fastest field check, followed by LWUV.
Where does Maxixe fit in the market?
Maxixe has a legitimate but narrow place in the coloured stone trade. It is a curiosity for collectors who understand and accept the fading behaviour, and who are prepared to store the stone appropriately. It has no legitimate place in daily-wear jewellery sold to a customer under the impression they are buying a stable stone.
The commercial risk of Maxixe entering the market as aquamarine is not hypothetical. It has happened repeatedly since the 1970s, when artificially irradiated Maxixe-type material began appearing in Brazilian and Asian trading centres, and it continues to happen wherever supply chain oversight is thin. The best defence against it is the same defence against most treatment-related pitfalls: sourcing from reputable suppliers whose gemmological expertise you trust, and requesting laboratory documentation for any purchase where the value justifies it.
If you would like to discuss aquamarine sourcing, or you have a stone you would like assessed for Maxixe characteristics, we are happy to help. A quick conversation before a purchase is always cheaper than a return and a reputation to repair afterward.