Keokuk geodes are famous for their hollow, spherical limestone exteriors filled with sparkling, druzy quartz or chalcedony crystals. They are typically found by splitting the nodule to reveal a variety of crystal formations, including clear quartz points, banded agate, or colorful mineral inclusions like calcite and dolomite.
Is this keokuk geode?
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 keokuk geode with a known reference. Keokuk Geode 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. Keokuk Geode leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Keokuk Geode typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: clear, white, gray, brown, blue, purple.
- 5Look at form & habitCrystal system: trigonal. Typical habit: druzy.
Often confused with
Keokuk Geode vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside keokuk geode
Minerals reported to co-occur with keokuk geode. 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
- 2.65 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Trigonal
- Crystal habit
- Druzy
- Cleavage
- None
- Rarity
- Common
- Uses
- Collector, Decorative, Lapidary
- Host rock
- Warsaw Formation Limestone
- Typical price
- $10-100 per specimen
Where rockhounds find keokuk geode
4 mapped spotsClassic worldwide localities
- Keokuk, Iowa
- Hamilton, Illinois
- Clark County, Missouri
Field-hunting tip
Look in warsaw formation limestone country — that is the host setting where keokuk geode typically forms. If you start seeing calcite, dolomite, kaolinite in float, you are in the right ground. Field specimens usually show a druzy habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Iowa — start trip planning there.
Common questions
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Find keokuk geode on the map
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