Falgarite is a specific type of fulgurite formed by lightning strikes hitting nitrogen-rich organic material or soil, resulting in a glass-like substance. It typically presents as brittle, tubular glassy formations that preserve the path of the electrical discharge through the ground. Collectors look for intricate, branching structures that are often found in sandy or loose soil environments.
Is this falgarite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch falgarite with a known reference. Falgarite sits at Mohs 3-4 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Falgarite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Falgarite typically shows a glassy luster.
- 4Match the color rangeCompare against the expected color range: white, yellow, brown.
- 5Look at form & habitCrystal system: amorphous. Typical habit: fulgurite-like tubes, crusts.
Often confused with
Falgarite vs. its common look-alikes — and how to tell them apart in the field.
All properties
- Chemical formula
- SiO₂
- Mohs hardness
- 3-4
- Density
- 2.1-2.2 g/cm³
- Streak
- White
- Luster
- Glassy
- Transparency
- Translucent
- Crystal system
- Amorphous
- Crystal habit
- Fulgurite-like Tubes, Crusts
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector, Scientific Research
- Host rock
- Sedimentary Deposits
- Typical price
- $20-150 per specimen
Where rockhounds find falgarite
Classic worldwide localities
- Germany
- United States
Field-hunting tip
Look in sedimentary deposits country — that is the host setting where falgarite typically forms. If you start seeing sand, soil components in float, you are in the right ground. Field specimens usually show a fulgurite-like tubes, crusts habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find falgarite on the map
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