Rock
Breccia
Breş
A rock broken and glued back together: its sharp, angular pieces tell of landslides, faults, volcanoes and asteroid impacts.
- Ornamental
In short
Breccia is a rock made of angular broken pieces stuck together by a fine-grained matrix or a natural cement. Its pieces have not been rounded, which shows that they were buried close to where they broke, without travelling far. Some breccias are used as decorative stone because their colourful fragments make a mosaic pattern.
How does it form?
Breccia fragments are angular because they have moved little or not at all from where they broke. Many processes can shatter rock like this:
- Sedimentary breccia: scree at the foot of cliffs, landslide debris and the rubble of collapsed cave roofs become cemented over time.
- Fault (tectonic) breccia: blocks of rock grinding past each other along a fault crush the rock into pieces.
- Volcanic breccia: lava and rock blasted apart in explosive eruptions are welded together or bound by ash.
- Impact breccia: large asteroid impacts smash rock to pieces; the suevite of Germany’s Ries crater is a famous example.
Water seeping through the gaps leaves behind calcite, silica or iron oxide, which binds the fragments together again.
Breccia in Türkiye
Breccia corallina, a favourite decorative stone of Roman times, was quarried near Vezirhan in today’s Bilecik, close to a tributary of the Sakarya River. This limestone breccia, known for its orange to salmon-pink matrix and calcite veins, was shipped to Rome from the reign of Augustus onwards and used for columns, wall cladding and floors. A beige limestone breccia with thin orange veins is still quarried in the area today.
How to recognise it
- 1
It is made of sharp-edged, angular fragments you can see, usually of very different sizes.
- 2
The fragments and the matrix between them are often different colours, giving the rock a mosaic look.
- 3
Breccias made of limestone or marble fragments fizz in dilute acid and can be scratched with a knife; siliceous breccias do not fizz and scratch glass.
- 4
It differs from conglomerate in the shape of its pieces: conglomerate has rounded pebbles, breccia has angular fragments.
Fakes and imitations
What shops usually don’t tell you:
- Many decorative stones sold as “breccia marble” are, geologically, limestone or marble that was shattered and re-cemented by calcite; trade names do not always follow scientific classification.
- Engineered (composite) stone made of marble chips bound with resin or cement looks like breccia, but its chips are more evenly spread and the binder between them is uniform.
- On breccia-look porcelain tiles the pattern is only on the surface and repeats every few tiles.
Did you know?
St George's Church in Nördlingen, Germany, is built of suevite, a breccia formed by an asteroid impact about 15 million years ago; the stone contains microscopic diamonds.
The word “breccia” is Italian for broken stone or rubble.
Where is it found?
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- Vezirhan, Bilecik, Türkiye · Historic sourceSource of “breccia corallina”, a limestone breccia with an orange to salmon-pink matrix known to the Romans as “marmor Sagarium” and shipped to Rome. A beige limestone breccia is still quarried in the area.
- Nördlingen (Ries crater), Bavaria, Germany · Known localityThe impact breccia suevite was first recognised in this crater, formed by an asteroid impact about 15 million years ago. The town's St George's Church is built of it.
- Mosaic Canyon, Death Valley, California, USA · Known localityThe canyon is named after its breccia, a mosaic of angular fragments of many different rocks.
Locations are approximate to protect sites. Red dots mark places in Türkiye. Open in the big map →
Sources
- Breccia · Encyclopaedia Britannica
- Corsi Collection of Decorative Stones — Breccia corallina (Corsi 404) · Oxford University Museum of Natural History
- Explorer's Guide to Impact Craters — Ries: Nördlingen · Planetary Science Institute
- Mosaic Canyon · U.S. National Park Service
External links
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