Moldavite — A Green Splash from a Very Bad Day
Moldavite is natural impact glass formed when a meteorite slammed into what is now southern Germany, melting surface rocks and ejecting droplets of green, silica‑rich melt across Central Europe. Those droplets quenched mid‑flight into glass and later weathered into the sculpted, bottle‑green pieces so many collectors love. It’s geology’s split‑second artwork: one cosmic strike, millions of tiny green souvenirs. (The Earth didn’t enjoy the day; our display shelves did.)
Identity & Naming 🔎
Tektite, not volcanic glass
Moldavite is a tektite—a natural impact glass—not a volcanic glass like obsidian. Its composition reflects melted terrestrial rocks blasted into the air by the Nördlinger Ries impact and quenched so fast that crystals never had time to form.
Where the name comes from
The name derives from the German “Moldau,” the Vltava River that runs through the Czech Republic, near classic finds. Hence: moldavite—“the glass from Moldau country.”
How It Forms (Impact Story) ☄️
1) Impact & melting
A meteorite struck the region ~14.8 million years ago, excavating the Ries crater. Heat and pressure melted surface sediments and rocks into a glowing splash of silicate liquid.
2) Ejection & flight
Jets of melt were ejected at high speed and arced downrange (NE). In the air, droplets stretched, spun, and quenched to glass within seconds.
3) Landing & weathering
Glass landed across parts of today’s Czech Republic, Austria, and Germany—the strewn field. Later, groundwater etched the surfaces into the pitted, sculptural textures collectors prize.
Impact art: a single cosmic brushstroke, millions of green dots on the landscape.
Appearance & Texture 🎨
Palette & transparency
- Bottle/forest green — most common.
- Olive/khaki green — Fe‑rich zones.
- Light green — thinner pieces, Bohemian material.
- Brown‑green — more typical of some Moravian finds.
Most specimens are translucent to locally transparent. Hold one to the light and you’ll see a glowing green tea color with tiny bubbles suspended inside.
Shapes & surfaces
- Discs, droplets, dumbbells—aerodynamic “splashform” shapes from flight.
- Etched sculpture—micropits, grooves, and ridges from soil acids over geologic time.
- “Hedgehog” rough (spiky, deeply etched) from localities like Besednice—famous and much imitated.
Photo tip: Back‑light with a small LED through a thin edge. Moldavite turns into a green lantern and the bubbles pop into view.
Physical & Optical Properties 🧪
| Property | Typical Range / Note |
|---|---|
| Type | Tektite (natural impact glass); silica‑rich with Al, K, Fe |
| Structure | Amorphous; contains lechatelierite (pure silica glass) streaks |
| Hardness | ~5–5.5 (brittle; chips with sharp blows) |
| Specific gravity | ~2.32–2.38 |
| Refractive index | ~1.48–1.51 (similar to other natural glasses) |
| Fracture | Conchoidal—curving “shell” breaks with razor edges |
| Inclusions | Elongated bubbles; wispy, colorless lechatelierite strings; flow lines |
| Magnetism | Non‑magnetic |
Under the Loupe 🔬
Flow & schlieren
At 10×, look for flow lines—wispy, parallel streaks—plus schlieren (streaky variations in clarity) recording turbulent cooling.
Lechatelierite “threads”
Colorless, worm‑like silica glass strings (lechatelierite) are classic in genuine moldavite. They look like frozen, gossamer filaments inside.
Bubbles & surface etching
Expect elongated or tear‑shaped bubbles, not just perfect spheres. Natural surfaces show irregular micropits and channels, not repeating tool marks.
Authenticity & Common Fakes 🕵️
Bottle glass & casts
Bright, uniform neon green with mold seams, perfectly round bubbles, and glossy surfaces are red flags. Cast pieces may show repeating textures and lack internal lechatelierite.
Artificial “etching”
Acid‑etched glass can mimic pitting but often looks evenly frosted or “orange‑peel” smooth. Natural sculpture is chaotic—deep grooves next to delicate pits.
Quick checklist
- Inside: flow lines + lechatelierite wisps + mixed bubble sizes/shapes.
- Surface: non‑repeating micropits and channels; no seam lines.
- Color: natural, slightly olive; edges glow green‑tea under light.
Localities & Strewn Fields 📍
Bohemia (South & West)
Classic green pieces from the South Bohemian field (e.g., around Chlum, Besednice, Ločenice) and parts of West Bohemia. Many show bright transmission color and intricate natural sculpture.
Moravia & beyond
Moravian moldavites (around Brno/Třebíč region) are often larger and darker olive‑green to brown‑green, with more aerodynamic “splashform” shapes. Scarcer pieces occur in Lower Austria and parts of Germany downrange from the Ries.
Care & Handling 🧼
Everyday handling
- Brittle glass: avoid drops and sharp knocks.
- Edges on chips can be razor‑sharp—handle like fine glass art.
Cleaning
- Lukewarm water + mild soap; soft brush for micropits; rinse and dry.
- Avoid harsh acids/alkalis and ultrasonic cleaners.
Storage & display
- Store separately from quartz/corundum neighbors to protect the surface.
- Back‑lighting or side‑lighting at ~30° makes bubbles and threads glow.
Hands‑On Demos 🔍
Green‑tea test
Shine a flashlight through a thin edge: the interior should light up a clear green‑tea hue with tiny, wandering bubbles.
Schlieren safari
Under a loupe, slowly rotate the piece. Track the lechatelierite threads and flow lines as they shift—your window into seconds of flight long ago.
Small joke: moldavite is the universe’s way of saying “sorry about the crater—have some glass.”
Questions ❓
Is moldavite from space?
The energy came from space, but the glass is melted terrestrial rock thrown skyward by the impact.
Why are some pieces wildly sculpted and others smooth?
Time buried in different soils matters. Acidic, sandy soils etch spectacular textures; pieces preserved in clays or gravels may look smoother.
Can moldavite be fully transparent?
Thin, high‑quality fragments can be very clear, but bubbles and wisps are normal and part of the identity.
How is it different from green obsidian?
Green obsidian is volcanic; moldavite is impact glass with lechatelierite threads and a specific Central European provenance tied to the Ries event.
Does the color fade?
No—color is inherent to the glass chemistry and thickness. Keep surfaces clean and scratch‑free for best glow.