Coquina is a sedimentary rock composed almost entirely of poorly cemented shell fragments and mollusk debris. It is easily identified by its highly porous, conglomerate-like appearance and its distinct lack of a fine-grained matrix. It is commonly found in beach and shallow marine environments where high wave energy prevents the accumulation of silt.
Is this coquina?
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 coquina with a known reference. Coquina sits at Mohs 3 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Coquina leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Coquina typically shows a dull luster.
- 4Match the color rangeCompare against the expected color range: tan, white, light gray.
- 5Look at form & habitTypical habit: massive.
Often confused with
Coquina vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside coquina
Minerals reported to co-occur with coquina. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Mohs hardness
- 3
- Density
- 2.0-2.5 g/cm³
- Colors
- Streak
- White
- Luster
- Dull
- Transparency
- Opaque
- Crystal habit
- Massive
- Cleavage
- None
- Rarity
- Common
- Uses
- Construction, Decorative, Ornamental
- Host rock
- Marine Environments
- Typical price
- $5-30 per specimen
Where rockhounds find coquina
2 mapped spotsClassic worldwide localities
- Florida, USA
- Saint Augustine, USA
- Western Australia
- Brazil
- Spain
Field-hunting tip
Look in marine environments country — that is the host setting where coquina typically forms. If you start seeing calcite, quartz, aragonite in float, you are in the right ground. Field specimens usually show a massive habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Florida — start trip planning there.
Common questions
How do you identify coquina?+
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Find coquina on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
