The Thermes of Antonino or Thermes of Carthage (2nd century) were one of the most important baths of the Roman era, and the largest baths built on African soil. For the construction of its columns were used materials such as white marble, gray granite and red granite brought from Egypt.
THE GRANITE
Granite is a plutonic igneous rock formed essentially by quartz, alkali feldspar, plagioclase and mica.The word "granite" comes from the Latin granum, a grain, in reference to the coarse-grained structure of such a holocrystalline rock.
Granite sensu stricto refers to rocks that, within the previous group, have a relationship between both classes of feldspars - alkaline and plagioclase - from 50% or more favorable towards alkali feldspars. Depending on this proportion, the granites are called:
- Alkaline feldspar granite, if more than 90% of all feldspars are alkaline
-syenogranite, if the proportion is greater than 65% of alkali feldspars
-monzogranite, up to an equal proportion between alkali feldspars and plagioclase. 
Granitoids are formed by solidifying magma with high silica content - what is known as saturated magma - deep beneath the earth's crust, under conditions of high pressure and slow cooling. If a magma of granite composition reaches the surface, a volcanic rock called rhyolite forms. 
THE MARBLE
Marble is a compact metamorphic rock formed from limestone rocks that, subjected to high temperatures and pressures, reach a high degree of crystallization. The basic component of marble is calcium carbonate, whose content exceeds 90%; the other components are those that give a great variety of colors in the marbles and define their physical characteristics. After a polishing process by abrasion, the marble reaches a high level of natural shine, that is, without waxes or chemical components. Marble is mainly used in construction, decoration and sculpture. Sometimes it is translucent, of different colors, such as white, brown, red, green, black, gray, yellow, blue, and may appear uniform in color, marbled (with flecks), veined (hatched lines) and various configurations or mixtures between them.
🌍In the coordinates you will find columns of red granite brought from Egypt and in particular one that is in the ground divided into three parts. - What texture does it have in the cuts and what color besides the red predominates in its granulometry?
🌍Find the large column of the "frigidarium" which is 15 meters high. -What material do you think is built? And its base?
🌍You can also see a piece of frieze with a monumental inscription that mentions the improvements made under the rule of Marco Aurelio and Lucio Vero. - What material do you think is built?
