How to identify fake Moldavite
There are several ways to scientifically distinguish real moldavite from fake. Many require laboratory instruments, but there's also a simple method accessible to everyone. We firmly believe in fighting fake moldavites: here's how to protect yourself.
01Ultraviolet (UV) Light
Natural moldavite is inert to both shortwave and longwave UV: it does not fluoresce. Fake moldavite, however, shows a faint whitish fluorescence under shortwave UV. Under longwave UV, both real and fake moldavite remain inert.
☢️ New: Uranium Glass Fakes
Recently, fakes made of uranium glass (uranium/vaseline glass) have appeared: a greenish-yellow glass containing uranium oxide which, under a UV lamp, emits an intense green glow. For us, this is almost a gift: since authentic moldavite never fluoresces, a specimen that glows bright green under a Wood's lamp is most likely a uranium glass fake. No need for alarm—the radioactivity of these glasses is generally very low—but it's still glass, not moldavite.
02Refractive Index
This is a reliable test, but difficult to apply to raw natural moldavite due to its irregular surface. The refractive index of real moldavite is 1.490 (from 1.480 to 1.510), compared to approximately 1.520 for fake moldavite.
03Raman Spectrometry
Raman spectrometry analyses show that real moldavite has a peak around 460 cm⁻¹, while fake moldavite shows two peaks, around 560 cm⁻¹ and 1100 cm⁻¹.
04Lechatelierite
Lechatelierite is visible to the naked eye in faceted or polished moldavite. It is rarely seen in natural moldavite due to the surface sculpture, although it can sometimes emerge on the surface as a tiny crystalline point: in that case, a very high magnification instrument, such as a microscope, is needed.
The key characteristic: in real moldavite, lechatelierite always follows the flow lines of the stone, running in a single direction. In fakes, however, the flow tends to swirl or go in multiple directions, or is completely absent (as in bottle glass).
The flow lines in a real faceted moldavite
05Experience and Expert Consultation
Anyone who has handled thousands of moldavites from dozens of different locations has the experience and sensitivity to recognize what is authentic at a glance. Here's how to build your confidence:
- Join a Facebook group dedicated to moldavite and post your photos for opinions: take them from multiple angles, in natural light and with backlighting.
- Educate yourself: learn what real moldavite looks like by consulting reputable online stores. Do not use marketplaces like eBay, Etsy, or AliExpress to "study," as they are full of fakes.
- Learn to recognize fakes too: you can find over a hundred examples in our gallery of fake moldavites.
✅ What is the best method?
The most accessible way to tell if a moldavite is authentic is Method 5: building your own knowledge and relying on expert experience. For faceted moldavite, however, the most effective and immediate method is lechatelierite (Method 4).
06Methods that DO NOT work
Polariscope to measure internal stress
The polariscope detects internal stress due to glass cooling. Primary forms (drops, discs, dumbbells) have high internal stress visible under the polariscope — but a fake of the same shape shows the same stress. And fragments, real or fake, often show none at all.
"Feeling the energy"
Relying on the sensation of perceiving energy is not a reliable method: the placebo effect comes into play, where the mind creates the experience it expects. It's no coincidence that many people swear they "feel the energy" even from fake pieces. Often what we perceive is simply a greater awareness of the body: if you concentrate your attention on your hand, you might feel a tingling sensation that was already there — it's just your attention bringing it to the forefront.
Gem identification apps
Apps like Rock Identifier, Gem AI, or Gemius compare the stone's photo with an image database. But tektites (like moldavite) are often poorly represented, so the app defaults to the "most similar" gem. They cannot detect internal structure, origin, or composition — all crucial factors. Useful for curiosity, not for authentication.
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When in doubt, ask an expert
For years, we have dealt only with authentic moldavite from dozens of Czech locations. If you have a doubt about a piece, we are here: better to ask one more question than to be disappointed.
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