Tektite, not volcanic glass

Moldavite is a tektite — natural impact glass, not volcanic glass like obsidian. Its composition reflects melted terrestrial rocks that the Nördlinger Ries impact threw into the air and cooled so quickly that crystals didn’t have time to form.

Name origin

The name derives from the German “Moldau” — the Vltava River in Czechia, near classic find sites. So: moldavite — “glass from the Moldau region.”

1) Impact and melting

About 14.8 million years ago, a meteorite struck the region and formed the Ries crater. Heat and pressure melted surface sediments and crystalline layers into glowing silicate melt.

2) Ejection and flight

Melt streams were ejected at high speed and flew in an arc away (to the northeast). In the air, droplets stretched, spun, and within seconds froze into glass.

3) Sedimentation and etching

Glass fell over today’s Czechia, Austria, and Germany — thus forming a strewn field. Later, groundwater etched the surface into pitted, sculptural textures admired to this day.

Palette and transparency

• "Bottle"/forest green — the most common.
• Olive/khaki green — iron-rich zones.
• Light green — thinner pieces, characteristic of Bohemia.
• Ruddy green — more common in some Moravian finds.

Usually semi-transparent to locally transparent. Hold against light — the interior glows with a green tea shade with fine bubbles.

Shapes and surfaces

• Discs, drops, "dumbbells" — aerodynamic splashform shapes from flight.
• Etched sculpture — micro-pits, grooves, and ridges from soil acids over geological time.
• "Hedgehog" raw material (spiky, deeply etched) from places like Besednice — famous and often imitated.

Photo tip: Illuminate with a small LED beam through a thin edge — moldavite turns into a green lantern, and bubbles become bright.

Flow lines and "schlieren"

At 10× look for flow lines — thin, parallel streaks — and schlieren (schlieren) — striped transparency changes capturing turbulent cooling.

Lechatelierite "fibers"

Colorless, wormlike silica glass fibers (lechatelierite) — a classic feature of real moldavite. They look like frozen spiderweb threads.

Bubbles and surface etching

Expect elongated or teardrop-shaped bubbles, not just perfect spheres. Natural surfaces show irregular micro-pits and channels, not repeating tool marks.

Bottle glass and castings

Bright, uniform neon green with casting seams, perfectly round bubbles, and glassy shiny surfaces — red flags. Castings often have repeating textures and lack internal lechatelierite fibers.

Artificial “etching”

Acid-etched glass can mimic pitting but often appears evenly matte or with an “orange peel” texture. Natural sculpture is more chaotic — deep grooves next to fragile pits.

Brief checklist

• Inside: flow lines + lechatelierite fibers + mixed size/shape bubbles.
• Surface: unique micro-pits and channels; no seams.
• Color: natural, slightly olive; edges glow with a “green tea” tone against the light.

Bohemia (southern and western)

Classic green flakes from the South Bohemia field (e.g., around Chlum, Besednice, Ločenice) and some Western Bohemia locations. Many feature a bright translucent shade and complex natural sculpture.

Moravia continued

Moravian moldavites (around Brno/Třebíč region) are often larger and darker olive–brownish in color, with more aerodynamic “splashform” shapes. Less common in Lower Austria and some parts of Germany south of the Ries crater.

Everyday cleaning

• Fragile glass: avoid drops and strong impacts.
• Edges of shards can be razor-sharp — handle like delicate glass art.

Cleaning

• Lukewarm water + drop of mild soap; soft brush for micro-cavities; rinse and dry.
• Avoid strong acids/bases and ultrasonic cleaning.

Storage and display

• Keep separate from quartz/corundum “neighbors” to protect the surface.
• Illuminate from behind or ~30° side light — fibers and bubbles will sparkle.

“Green tea” test

Light through a thin edge with a flashlight: the interior should glow with a transparent green tea color with small, wandering bubbles.

Shliri safari

Slowly rotate the piece under a magnifier. Follow the lechatelierite fibers and flow lines as they change — a window into a few seconds of flight millions of years ago.