Fossilized coral occurs when ancient coral colonies are replaced by microcrystalline silica, preserving the original cellular structure of the polyp heads. Collectors look for distinct floral-like patterns on the surface, which are best revealed after cutting and polishing. It is commonly found in regions with ancient shallow marine environments that have undergone significant silicification processes.
Is this fossilized coral?
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 fossilized coral with a known reference. Fossilized Coral 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. Fossilized Coral leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Fossilized Coral typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: white, gray, brown, red, pink, orange, yellow.
- 5Look at form & habitTypical habit: botryoidal.
Often confused with
Fossilized Coral vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside fossilized coral
Minerals reported to co-occur with fossilized coral. 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
- 2.6-2.7 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal habit
- Botryoidal
- Cleavage
- None
- Rarity
- Common
- Uses
- Lapidary, Collector, Decorative, Jewelry
- Host rock
- Sedimentary Environments Where Silica-rich Fluids Replaced Ancient Coral Reefs
- Typical price
- $5-50 for rough, $20-200 for polished cabochons or display pieces
Where rockhounds find fossilized coral
10 mapped spotsClassic worldwide localities
- Florida, USA
- Indonesia
- Utah, USA
- Texas, USA
- Thailand
Field-hunting tip
Look in sedimentary environments where silica-rich fluids replaced ancient coral reefs country — that is the host setting where fossilized coral typically forms. If you start seeing quartz, calcite, chalcedony in float, you are in the right ground. Field specimens usually show a botryoidal habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Florida, California, Indiana — start trip planning there.
Common questions
How do you identify fossilized coral?+
Where is fossilized coral found?+
Can I find fossilized coral in the United States?+
How much is fossilized coral worth?+
What rocks look like fossilized coral?+
What minerals are found with fossilized coral?+
What kind of rock does fossilized coral form in?+
What is fossilized coral used for?+
Find fossilized coral on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
