Coral (Fossil & Precious)
Coral (Fossil & Precious) is biogenic carbonate (or agatized fossil), CaCO₃ (agatized: SiO₂). In the hand, it rates 3 to 4 (agatized: 6.5 to 7) on the Mohs scale, and it runs white and tan flower patterns. Stone covered in small repeating flower- or honeycomb-like polyp patterns, fossil colonies frozen in carbonate or silica.
The geology.
Coral (Fossil & Precious) carries the formula CaCO₃ (agatized: SiO₂). It belongs to the, system. Its listing category is biogenic carbonate (or agatized fossil).
It sits at 3 to 4 (agatized: 6.5 to 7) on the Mohs scale. The surface reads waxy to dull. Light behaviour is opaque. Specific gravity runs 2.6 to 2.7. The streak is white. It breaks with uneven fracture.
Stone covered in small repeating flower- or honeycomb-like polyp patterns, fossil colonies frozen in carbonate or silica.
It turns up mostly as agatized coral tumbles, polished fossil slabs or beads (precious coral).
The origins.
Fossil coral: Indonesia, Florida (USA), Morocco; precious red: Mediterranean (heavily regulated).
On value, the database notes: fossil coral affordable; genuine precious red coral is costly and ethically fraught.
Traditional associations.
In energy work traditions, associated with community and ancestral connection.
This is lore, and we label it as lore. The measurable facts are further up the page.
Spotting the real thing.
Stone covered in small repeating flower- or honeycomb-like polyp patterns, fossil colonies frozen in carbonate or silica.
Red coral is widely dyed or imitated, and harvest is restricted, fossil/agatized coral is the ethical, common form in shops.
| Looks like | How to tell them apart |
|---|---|
| Dyed bamboo coral | Most cheap red coral beads are dyed white bamboo coral, dye shows in pits and on string |
| Resin/plastic 'coral' | Warm, light, and bubble-bearing; real coral is cool and dense |
| Flower agate | Flower agate blooms are random chalcedony plumes, not repeating polyp grids |
At-home tests.
A loupe and a window seat settle most questions about coral (fossil & precious). No workshop required.
| Test | What you should see |
|---|---|
| Scratch check | Carbonate coral fizzes in vinegar; agatized coral does not and scratches glass |
| Under a loupe | Repeating polyp pattern under a loupe |
| By touch | Cold stone feel |
Anything that scratches, burns or dissolves the piece is a lab job. Get it appraised rather than testing it apart.
Care & handling.
At 3 to 4 (agatized: 6.5 to 7) on the Mohs scale this is a soft material. Keep it as a display piece, store it apart from harder stones, and skip daily-wear settings.
It breaks with uneven fracture, which is worth knowing before you set it or drop it.
Warm water and a soft cloth clean almost everything. Ultrasonic tanks, steamers and household cleaners are where pieces get ruined.
A deeper look.
Extended detail on composition, sourcing, authentication and market value.
The physical record
The formula on record is CaCO₃ (agatized: SiO₂). Crystal system:,. Specific gravity: 2.6 to 2.7. Streak: White. Cleavage and fracture: Uneven fracture.
How it reaches the market
Fossil coral: Indonesia, Florida (USA), Morocco; precious red: Mediterranean (heavily regulated).
What it gets confused with
Dyed bamboo coral: Most cheap red coral beads are dyed white bamboo coral, dye shows in pits and on string. Resin/plastic 'coral': Warm, light, and bubble-bearing; real coral is cool and dense. Flower agate: Flower agate blooms are random chalcedony plumes, not repeating polyp grids.
What it is worth
Fossil coral affordable; genuine precious red coral is costly and ethically fraught.
Where buyers get caught
Red coral is widely dyed or imitated, and harvest is restricted, fossil/agatized coral is the ethical, common form in shops.
One more thing
Florida's state stone is agatized coral, reef animals replaced molecule-by-molecule with quartz.
An education-first guide.
No product links here. We do not sell coral (fossil & precious), and a guide that only covers our own shelves would not be much of a guide.
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