White chert is a microcrystalline variety of silica that typically forms as nodules within chalk or limestone formations. It is well-known to rockhounders for its characteristic conchoidal fracture and history as the primary material for stone tool-making, such as arrowheads and scrapers.
Is this white chert?
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 white chert with a known reference. White Chert sits at Mohs 6.5-7 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. White Chert leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. White Chert typically shows a waxy luster.
- 4Match the color rangeCompare against the expected color range: white, cream, grayish-white.
- 5Look at form & habitCrystal system: trigonal. Typical habit: massive, nodular, concretionary.
Often confused with
White Chert vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside white chert
Minerals reported to co-occur with white chert. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- SiO₂
- Mohs hardness
- 6.5-7
- Density
- 2.6-2.65 g/cm³
- Colors
- Streak
- White
- Luster
- Waxy
- Transparency
- Opaque
- Crystal system
- Trigonal
- Crystal habit
- Massive, Nodular, Concretionary
- Cleavage
- None
- Rarity
- Common
- Uses
- Lapidary, Decorative, Historical Tool-making
- Host rock
- Sedimentary (chalk and Limestone Beds)
- Typical price
- $1-20 for rough specimens, depending on size and inclusions
Where rockhounds find white chert
1 mapped spotsClassic worldwide localities
- United Kingdom
- France
- United States
- Denmark
- Belgium
Field-hunting tip
Look in sedimentary (chalk and limestone beds) country — that is the host setting where white chert typically forms. If you start seeing calcite, dolomite, quartz in float, you are in the right ground. Field specimens usually show a massive, nodular, concretionary habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Missouri — start trip planning there.
Common questions
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Find white chert on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
