Tectonic breccias in the commercial decorative stone trade are typically called “marbles”. By definition, any breccia will have abundant large angular fragments. The tectonic breccias are generated by intense tectonic crushing and fracturing along fault zones in orogenic belts. Cut & polished samples are typically bicolored or multicolored and are quite striking in appearance.
French Grand Antique Marble (field of view 10.9 cm across) - an attractive black & white tectonic limestone breccia from southern France. It has large to small angular fragments of black micritic limestone surrounded by whitish carbonate cement. It has been quarried for millennia (known Roman names for this rock include “Marmor Celticum” and “Marmor Aquitanicum”). The rock was exploited in Roman & Byzantine times, then abandoned and forgotten. Quarrying resumed after rediscovery in the 1700s, but the area is now exhausted (it’s an “extinct” rock). This material came from an old quarry at Aubert, just southeast of Moulis, Lez River Valley, southwest of Saint-Girons, western Ariège Department, central Pyrenees Mountains, far-southern France.
Italian Red Antique Marble - a tectonic marble breccia from Italy having white calcite veining and some greenish serpentinization. This material comes from Genoa in Liguria Province, northwestern Italy.