In Geology "marble" is defined as "a metamorphic rock consisting predominantly of fine -to coarse- grained recrystallized calcite and/or dolomite, usually with a granoblastic, saccharoidal texture". But "marble" in commerce groups also many other rocks that differ from the above metiones definition. Most of these are sedimentary carbonatic rocks, limestones or dolostones more or less recrystallized or marmoreal, but many other do not belong to the same genetic group, for example certain serpentines are known commercially as "green marble".
Spanish marbles "sensu stricto" outcrop in the metamorphic areas of the Hesperian Massif (Western Iberian Peninsula), Betic Range (Southeastern Spain) and in a small area in the Axial Zone of the Pyrenees (Northeast Spain). This marbles are ancient rocks dating from the Precambrian to the Paleozoic ages.
Marmoreal limestones and dolostones crop widely in the externs extension of the Pyrenees (Basque-Cantabrian Basin), in the Central Prepyrenee, in the Eastern Iberian Range and in the Betic Ranges, this rock are younger than the marbles, mainly from Jurasic-Cretacic age, although the marmoreal black limestones in the Pyrenees are of carboniferous age (Paleozoic) and the travertines and false agate are very modern (Quaternary).
Alabaster, wich is not a carbonatic rock, but a scarce variety of gypsum, is exploited in the Ebro valley and its age is Tertiary (upper Oligocene). Its inclusion in this catalogue is due to the fact that the word alabaster, from ancient times, designates two different minerals: calcite (calcareous alabaster) and gypsum (gypsum alabaster). Spanish alabaster is employed specially in sculpture and interior ornamentation, and most of the production is being exported.
The extraction and treatment of marbles and marmoreal limestones is an economical activity of first order in Spain. The production value of the materials has grown four times in the last few years. Taking account of this the I.T.G.E. presents this new catalogue as an updated and enlarged revision of that published in 1986, already out of print.
This catalogue has a first part, wich includes the historical aspects of the use of marble in architecture and sculpture, a general map with the location of the spanish quarries and a brief description of the tests this materials should be subjected to for its technological characterization. You can find also the files for each catalogued variety, with a photography and their technological characteristics and classification.
This catalogue is mainly technical and divulgative, and the information there in contained was selected with objective criteria and it is independent of commercial interests.
