heritage Review The Forerunners on Heritage Stones Investigation: Historical Synthesis and Evolution David M. Freire-Lista 1,2 1 Departamento de Geologia, Escola de Ciências da Vida e do Ambiente, Universidade de Trás-os-Montes e Alto Douro, 5001-801 Vila Real, Portugal; [email protected] 2 Centro de Geociências, Universidade de Coimbra, 3030-790 Coimbra, Portugal Abstract: Human activity has required, since its origins, stones as raw material for carving, con- struction and rock art. The study, exploration, use and maintenance of building stones is a global phenomenon that has evolved from the first shelters, manufacture of lithic tools, to the construction of houses, infrastructures and monuments. Druids, philosophers, clergymen, quarrymen, master builders, naturalists, travelers, architects, archaeologists, physicists, chemists, curators, restorers, museologists, engineers and geologists, among other professionals, have worked with stones and they have produced the current knowledge in heritage stones. They are stones that have special significance in human culture. In this way, the connotation of heritage in stones has been acquired over the time. That is, the stones at the time of their historical use were simply stones used for a certain purpose. Therefore, the concept of heritage stone is broad, with cultural, historic, artistic, architectural, and scientific implications. A historical synthesis is presented of the main events that marked the use of stones from prehistory, through ancient history, medieval times, and to the modern period. In addition, the main authors who have written about stones are surveyed from Citation: Freire-Lista, D.M. The Ancient Roman times to the middle of the twentieth century. Subtle properties of stones have been Forerunners on Heritage Stones discovered and exploited by artists and artisans long before rigorous science took notice of them and Investigation: Historical Synthesis explained them. and Evolution. Heritage 2021, 4, 1228–1268. https://doi.org/10.3390/ Keywords: archeology; geology; fortification; durability; conservation; quarries; restoration; architecture heritage4030068 Academic Editors: Carlos Alves, Carlos Figueiredo and 1. Introduction Jorge Sanjurjo-Sánchez Stones have been the subject of analysis since humans have sought the best shelters such as escarpments, caves and inverted slopes to protect themselves from inclement Received: 11 May 2021 weather [1]. Therefore, mankind has explored and exploited building stones throughout Accepted: 1 July 2021 Published: 12 July 2021 history [2–4]. The best-preserved records of human activity are those carved on this material. Much of the current knowledge of the oldest civilizations is due to the study of Publisher’s Note: MDPI stays neutral their heritage stones. The stones that today are considered heritage stones were used by with regard to jurisdictional claims in humans mainly as building stones and sometimes they were used for purposes other than published maps and institutional affil- those they have today. iations. The importance of stones is evidenced by the pre-Roman roots Mor (r), Mur (r), Mour present in numerous place names of Iberian Peninsula. For example, La Moraleja, Mata- moros, Moralzarzal, Moratalla, Montemuro, Moreiras, Morro, Mouçós, Moura, Mourelle, Murgi and Valdemoro, are names of localities linked to stone; material with which muros “walls” and moradas “dwellings” have been built since prehistoric times. The first stones Copyright: © 2021 by the author. Licensee MDPI, Basel, Switzerland. used as construction material came from the vicinity of the place where they would be used. This article is an open access article They were used as prehistoric tools [5,6], amulets [7], support for petroglyphs [8,9], projec- distributed under the terms and tiles [10], support for inscriptions of important events or laws [11], walls [12], monuments, conditions of the Creative Commons dikes, warehouses, paving [13] and all kinds of constructions [14]. Stones have also been Attribution (CC BY) license (https:// used to manufacture mortars [15–17], ceramics [18,19], bricks [20,21] and mosaics [22]. creativecommons.org/licenses/by/ Many ancient cities were built directly on quarries, resulting in harmony in between 4.0/). the landscape and the inhabited environment [23,24]. Exploitation of stones generated large Heritage 2021, 4, 1228–1268. https://doi.org/10.3390/heritage4030068 https://www.mdpi.com/journal/heritage Heritage 2021, 4 FOR PEER REVIEW 2 also been used to manufacture mortars [15–17], ceramics [18,19], bricks [20,21] and mosa- ics [22]. Many ancient cities were built directly on quarries, resulting in harmony in between Heritage 2021 4 , the landscape and the inhabited environment [23,24]. Exploitation of stones generated1229 large quarries from which they were extracted for export [25–27]. Some stones were trans- ported long distances and traded for their rarity and durability, [28,29] and some prehis- toricquarries quarries from have which survived they were to extractedthis day. for export [25–27]. Some stones were transported longThe distances study andof building traded stones for their has rarity evolved and from durability, a practical [28, 29way] and to make some ornaments, prehistoric tools,quarries houses, have temples survived an tod this infrastructures, day. among many other constructions to being the subjectThe of studyscientific of building research stones as we hasknow evolved it today. from The a study practical of heritage way to makestones ornaments, cannot be understoodtools, houses, without temples the and contribution infrastructures, of druids, among clergymen, many other quarrymen, constructions builders, to being natural- the ists,subject architects of scientific, archaeologists, research as physicists, we know itchemists, today. The curators, study restorers, of heritage engineers, stones cannot and ge- be ologists,understood who without have all the contributed contribution to of enriching druids, clergymen, our current quarrymen, knowledge builders, of heritage naturalists, stones. Whicharchitects, have archaeologists, been the subject physicists, of exposure chemists, and curators, study since restorers, the first engineers, museums and geologists,started to whoconserve have them, all contributed such as the to Ennigaldi enriching-Nanna our current museum knowledge in Mesopotamia, of heritage dating stones. from Which 530 BChave [30]. been the subject of exposure and study since the first museums started to conserve them,Some such examples as the Ennigaldi-Nanna of heritage stones museum have a in special Mesopotamia, relevance dating in human from culture. 530 BC For [30]. ex- ample,Some the examplesporphyries of from heritage Sweden stones and have Russia a special [31,32], relevance “Petit granit in human” and culture.Lede stones For fexample,rom Belgium the porphyries [33,34], slates from from Sweden the Iberian and Russia peninsula [31, 32[35],], “ PetitBath granitand Purbeck” and Lede limestones stones from England Belgium [36], [33,34 Sydney], slates sandstone from the Iberian[37], granites peninsula such [35 as], Piedra Bath and Berroqueña, Purbeck limestonesof Madrid (fromSpain England) [38–40] [ 36and], Sydney marbles, sandstone such as the [37], one granites from suchCarrara as Piedra in Italy Berroqueña, [41,42]. The ofse Madrid stones have(Spain) been [38 –widely40] and used marbles, and with such asthem the important one from Carrarabuildings in have Italy [been41,42 ].built These that stones have markedhave been the widelyhistory usedof humankind and with [43]. them important buildings have been built that have markedThis the work history is a ofhistorical humankind synopsis [43]. of the main events that marked the history of the use ofThis heritage work stones. is a historical It contains synopsis refer ofences the mainof the events main thatauthors marked who thehave history studied of thestones use inof the heritage ages of stones. human It history, contains focusing references on ofsouthern the main European authors countries, who have and studied without stones miss- in the ages of human history, focusing on southern European countries, and without missing ing the important development that research has had in the United States from the end of the important development that research has had in the United States from the end of the the 19th century to the 20th century. Scientists from a wide variety of disciplines contrib- 19th century to the 20th century. Scientists from a wide variety of disciplines contributed to uted to the current understanding of heritage stones, and the most important are men- the current understanding of heritage stones, and the most important are mentioned in tioned in this work. this work. 2. Stones and Religion Many myths compare stones to the “bones”“bones” ofof MotherMother Earth.Earth. Stone extractionextraction has been accompanied accompanied by by complex complex rituals rituals in indifferent different cultures cultures [44]. [44 Stones]. Stones have have also been also beenused inused healing in healing therapies therapies and in and numerous in numerous festivities festivities and pilgrimages. and pilgrimages. The Holy The Black Holy Stone Black (Stonecalled (called al-Hayar al-Hayar-ul-Aswad-ul-Aswad in Arabic in) Arabic) is a relic is that a relic according that according to Islamic to tradition Islamic tradition dates to thedates times to the of timesAdam of (Adam Adam) (Adam)and Hawa and (Eve Hawa). It (Eve).is a meteorite