A flint nodule is a mass of hard, cryptocrystalline quartz that forms within chalk and limestone sedimentary formations. Look for its distinctive conchoidal fracture and waxy luster, the qualities that historically made flint the preferred material for stone tools and fire starting.
Is this flint nodule?
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 flint nodule with a known reference. Flint Nodule sits at Mohs 7, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Flint Nodule leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Flint Nodule typically shows a waxy luster.
- 4Match the color rangeCompare against the expected color range: gray, black, brown, white.
- 5Look at form & habitCrystal system: trigonal. Typical habit: nodular.
Often confused with
Flint Nodule vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside flint nodule
Minerals reported to co-occur with flint nodule. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- SiO₂
- Mohs hardness
- 7
- Density
- 2.60-2.65 g/cm³
- Streak
- White
- Luster
- Waxy
- Transparency
- Translucent
- Crystal system
- Trigonal
- Crystal habit
- Nodular
- Cleavage
- None
- Rarity
- Common
- Uses
- Lapidary, Decorative, Historical Tool Making
- Host rock
- Chalk
Where rockhounds find flint nodule
2 mapped spotsClassic worldwide localities
- Dover England
- France
- Denmark
- United States
- Belgium
Field-hunting tip
Look in chalk country, the host setting where flint nodule typically forms. If you start seeing calcite, chalk, quartz in float, you are in the right ground. Field specimens usually show a nodular habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Ohio. Start trip planning there.
More flint nodule photos
Common questions
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Find flint nodule on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
