Liebau Prize awarded to Juan Manuel García-Ruiz

Wulf Depmeier

On the occasion of its annual conference in Munich, Germany (14–17 March 2022), the German Society for Crystallography (DGK) presented the Waltrude und Friedrich Liebau Prize for the Promotion of Interdisciplinarity in Crystallography for the year 2022 to Juan Manuel García-Ruiz, CSIC Professor at the University of Granada, Spain. Because of the COVID pandemic, the annual conference had to be held virtually, so the certificate could not, as usual, be handed over by the chairman of the DGK. As the award winner spent the first half of 2022 as a Senior Fellow at the Institute for Advanced Studies (Hanse-Wissenschaftskolleg, Bremen–Oldenburg), located in Delmenhorst, his host in nearby Bremen and co-author of important publications, Professor W. Bach (University of Bremen), agreed to hand over the certificate.

[Figure1]Professor García-Ruiz (left) with Professor Bach.

The decision of the prize committee to select the awardee was justified on the certificate with the following words translated into English:

“...for his fundamentally innovative considerations of the biological origin of microfossil structures as well as for his future-oriented examinations of chemical activity of self-organized mineral aggregates, which contribute to a new understanding of the importance of inorganic mineral building units for the development of natural biorelevant molecules under geochemical conditions and thus essential building blocks to establish a plausible prebiotic chemistry.”

In this context, the recently quoted advertisement for a W3 professorship at the Faculty of Geosciences of the Ludwig Maximilians Universität, Munich, is interesting, as it reflects the high topicality of the award, as the job description quoted in part explains:

“The Faculty of Geosciences of the Ludwig Maximilians Universität München invites applications for a Full Professorship (W3) of Mineral Earth and Life Interaction commencing on 01.04.2024. The Mineral Earth and Life Interaction professorship is intended to further strengthen the Faculty of Geosciences in the field of Earth and Environmental Sciences. Applicants are expected to have innovative and internationally visible research activities focused on the interaction of the mineral world and living organisms, as well as the ability to interface with the environmental sciences. Relevant research areas should cover the multi-scale structural relationships of biomaterials that contribute to a deeper understanding of the interaction of inorganic and biological processes. Research activities might include the formation of biomineral composites as well as processes that dissolve, convert and transform minerals. The focus should be predominantly on mineral components. It is desired that applicants employ state-of-the-art structural research methods, such as electron, photon, neutron or scanning microprobe techniques, atomic diffraction, nanoscale imaging and/or microchemical techniques.”

In addition to the certificate and the appropriate words of praise, the Liebau Prize comes with a considerable amount of prize money. The prize sponsors, Professor Friedrich Liebau from the University of Kiel, who died in 2011, and his wife Waltrude, provided the foundation with share capital and stipulated in the statutes that the prize money is to be raised from interest income or from donations or private donations. As is well known, interest rates have developed negatively over the past decade, so that there was a real danger that further award ceremonies would no longer be possible without access to capital, which was denied. Following a call from the Board of Directors, the members of the DGK unanimously agreed to a voluntary increase in the annual membership fees in order to raise the prize money. Incidentally, the same applies to the DGK’s Max von Laue Prize for young scientists, which is subject to similar conditions.

A more detailed appreciation of the awardee and his merits is included (in German) in Vol. 52 of the DGK-Mitteilungen and is available for download. The present short note confines itself to a few general remarks, and preferably those of topical relevance. Professor García-Ruiz is called Juanma by his friends. As I hope to count myself among them, I will occasionally use this name.

First, I would like to mention Juanma’s diverse activities to spread his profound knowledge about almost every aspect of crystallization to almost everyone. He not only shares his experience with his students and colleagues but also with school children of all ages, where he knows how to arouse interest and enthusiasm for crystals and their beauty. For the first category, there are the well known International Crystallization Schools of Granada, which are annually alternately inorganic or biologically oriented. For the second category, there are crystallization competitions for school children, whose sheer number of participants (approximately 14,000 annually in Spain alone) are self-explanatory. He also scores points with the lay public, where he has caused a stir in various media, for example, with his reports on the giant Naica crystals (El Misterio de los Cristales Gigantes: Edición comentada del guión de la pelicula Triana, Science and Technology 2015).

Juanma is very interested in promoting and cultivating connections between crystallography and related scientific communities. For example, in 2016 he led the first COSPAR–IUCr workshop on Crystallography for Space Sciences – an International School and Capacity Building Workshop held in Puebla, Mexico (BUAP) as well as in the nearby charming village of Tonantzintla, San Andrés Cholula, on the premises of the Instituto Nacional de Astrofísica, Óptica y Electrónica (INAOE). Hanna Dabkowska, current President of IUCr, attended the event as a representative of the union; see Hanna’s account in the 2016 IUCr Newsletter (old series). Incidentally,  I was also present. This was a welcome opportunity for me to look back on my first visit to Mexico (1981, after the 12th IUCr Congress in Ottawa, Canada) when I spent a pleasant few days in and around INAOE.

The COSPAR–IUCr workshop was organized under the auspices of the IUCr and IAU (International Astronomical Union), both members of the International Science Council (ISC). COSPAR is the abbreviation for the Committee on Space Research. Like other committees, it was established to assist the ISC and its 200+ member organizations in pursuing their respective scientific goals, should the specific competencies and skills of the committee be required. Therefore, the raison d'être of COSPAR is clearly interdisciplinary, and the purpose of the workshop was to familiarize young international students with some aspects of space exploration and its relation to crystallography. Participants received first-hand information from leading international specialists from various fields of space exploration. Among the numerous contributions, a special one deserves mention. This was the NASA Mars mission Mars Science Laboratory (start 2011) and its rover Curiosity. Participants with a keen interest in crystallographic methods were particularly attracted to CheMin, a portable and remote-controlled X-ray powder diffractometer tasked with studying Martian rocks on site. The CheMin project leader explained how the instrument works, and how the relevant data were transmitted over a distance of around 70 million kilometers to our planet for further study. A demonstration project was planned for the workshop, in which a replica of CheMin would be installed on the nearby Popocatépetl volcano. Sampling and diffraction would be carried out on site, and the data would then be transmitted to the INAOE for data analysis by the participants. Unfortunately, that plan fell victim to an unexpected event when the volcano entered a severe eruption phase. It could have been worse, as the eruption produced an intense ash rain so that the sampling could be carried out practically on the doorstep of the INAOE and the functionality of CheMin could be convincingly demonstrated.

One of the main themes of the workshop was the search for the origin of life on Earth and elsewhere. Professor García-Ruiz is one of the main players in this field of research, as evidenced by numerous publications. He is particularly intrigued by the possibility that inorganic materials may have played a major role and that both large-scale geological processes and widespread but small-scale physicochemical and catalytically controlled chemical reactions operate in confined volumes. Juanma was also involved in several aspects of planning for the ExoMars (Exobiology on Mars) mission. Organized under the leadership of the European Space Agency (ESA), this highly interdisciplinary project aims to search for traces, or perhaps even remnants (but likely extinct) of primitive life on Mars. It was hoped that this approach would provide clues as to whether primitive life forms might also have existed on the young Earth or whether they originated on the hitherto lifeless planet. The educated guess of geoscientists justifies this approach that Earth and Mars evolved more or less in parallel for the first ~500 million years after their formation, before Earth’s geodynamics set in, resulting in convection currents in the mantle and plate tectonics. Continuous formation and decay of the Earth’s crust would have destroyed all evidence of possible life. Mars is essentially unaffected by such dynamics, and possible remnants of early life would have stood the test of time there.

Juanma was elected IDS (Interdisciplinary Scientist) of the ExoMars project. This was because one of his main scientific interests was the investigation of self-organization phenomena in biological and geological structures, with possible implications for the origin of life. To appreciate the importance of crystallography for the planned investigations, the ExoMars rover was christened Rosalind Franklin. This was a tribute to the great scientist Rosalind Franklin (1920–1958) for her important work in connection with the elucidation of the structure of DNA. The launch window for ExoMars was planned for the period between August and October 2022. This plan fell victim to a side effect of the February 2022 Russian invasion of Ukraine. ESA, the leading science agency of the ExoMars project, decided to end the hitherto pleasant and successful cooperation with the Russian State Space Corporation Roscosmos. It is currently unclear when, or if, there will even be a future for ExoMars and the Rosalind Franklin.

To better characterize Juanma as a scientist, it makes sense to mention his activities in the Spanish program Explora, where he devised the concept and chaired the Scientific Advisory Board. Scientifically demanding projects that are risky in terms of achieving their goals are funded. Such projects often focus on the (blurred) boundaries between established scientific disciplines. Even if some projects will (honorably) fail, others can be successful and change established thinking and action. It might even be that this disrupts old ideas in favour of radically new emergent thinking. The Experiment! program of the Volkswagen Foundation and the Reinhart–Koselleck program of the German Research Foundation (DFG) seem to follow a similar approach.

Presumably, as a result of the approach described, Juanma seems to be deeply convinced that the border between the realm of crystals and that of living matter is not well defined and sharp, but blurred; there could be a gradual transition between both sides. In this context, it is appropriate to mention the research topic of Juanma during his stay at the Institute of Advanced Studies Bremen, Oldenburg, namely Biomorphs in Science and Art.

Following his belief, Juanma seems, supported by some evidence, to have developed an idea that crystals hold a certain special place in the totality of natural things, and that the contemplation of crystals might have provided a direction for the development of the early human mind. This would then have led to early forms of a sense of symmetry, beauty and later art, and possibly associated with various forms of transcendence. He has published the following interesting article on this, 2001: the Crystal Monolith, which is characterized by the following remarkable combination of keywords: crystals; crystallography; abstract thinking; paleoneurobiology; Kubrick, 2001: a Space Odyssey. The article provoked a comment from J. R. Helliwell: Wrestling with questions at the edge of science methods in the IUCr Newsletter in 2018 as well as an editorial comment by A. M. Glazer, where both recommended reading the article and reflecting on the ideas expressed there. (The author of these lines also later felt encouraged to write another comment entitled Some humble side-notes on quartz, handedness and possible evolution of the human mind in the IUCr Newsletter in 2019).

At the IUCr25 Congress in Prague (2021), Juanma gave a well received keynote lecture, building on his earlier works and which was supplemented by new ideas and historical evidence combined with experimental observations. The title also reflected his research topic at the Institute for Advanced Studies and was The crystal and the rose: on the influence of crystals and crystallography on art and mind. A summary can be found in Acta Cryst. A. He also reported the remarkable observation that not only infants, but also monkeys, have a clear tendency to prefer regularly shaped, or maybe even symmetrical, patterns over less regular or unsymmetrical ones. Juanma is planning corresponding systematic behavioral experiments on monkeys.

In a 2021 post for the IUCr Newsletter entitled Ancient crystal collectors, Juanma commented on a recent finding from palaeo-archaeologists. These findings seem to support his ideas about the possible relationship between crystal shape and consciousness-raising in hominins as our early ancestors. Juanma offers some arguments for an explanation of the find. I agree with most of them but tend to have a slightly dissenting opinion in a particular case. In his essay, he shows a photo of 30 or so calcite crystals that were excavated at a site in southern Africa and were obviously collected by hominins around 100,000 years ago and preserved by them for unknown purposes. All crystals in the photo are rhombohedrally shaped and their surfaces are more or less corroded by weathering. While well formed as-grown rhombohedral crystals of calcite are well known from other places in southern Africa. The occurrence of calcite in the close-by vicinity of the digging is reported to be restricted to massive crystal aggregates within a dolomitic limestone deposit. Therefore, the rhombohedral shapes were most probably formed by cleavage, either by accidental impact from the environment or caused intentionally by appropriate handling. The scientists involved in the excavation, and Professor García-Ruiz alike, seem to prefer the latter possibility and in addition, they are convinced that any usage of these crystals as primitive tools can be ruled out, given their poor mechanical properties (low hardness, cleavage). I agree with that. In addition, Juanma challenges the idea that optical properties might have drawn the hominins’ particular attention to the calcite crystals shown. Thereby, he focusses on birefringence, or double reflection, as a characteristic property of calcite, and he suggests that the poor quality of the finds prevented this effect from being observed. I agree, and one may add the likely underdeveloped technical skills of the hominins and the obstacles to finding suitable means for observing double reflection.

Instead of the latter rather tricky property, I would like to suggest another, more easily observed optical property, namely the reflection of light from flat surfaces. Mineralogists often use the different reflectivities, or luster, of minerals as a simple means for distinguishing between different mineral species. The perfect cleavage of calcite results not only in extremely flat surfaces but also in a particular luster on the rhombohedral cleavage planes. Because this is associated with iridescence, the luster is then labeled as pearl-like. The occurrence of iridescence requires crystals of the highest quality and freshly prepared cleavage planes. The effect lasts for only some time, after which the luster becomes less brilliant and loses the iridescence: the luster is then labeled glass-like. Nevertheless, such a cleavage plane is still highly reflective of sunlight. Because of the relatively low resistance of calcite to corrosion by water and particularly carbon dioxide, the flatness of the crystal faces, and hence the reflectivity, are likely to wane over the course of millenia, unless the crystals are protected from moisture.

As a particularly outstanding property, the reflected rays from a flat surface can be observed over a great distance – tens of meters or more – provided that the reflecting plane and the observer are properly oriented. In a figurative sense, one might then say that a kind of information channel has been opened between the crystal and the observer. Even a not-too-heavily corroded crystal surface can still be recognized by its luster. I suspect that this optical effect might have partially contributed to the attraction of calcite to hominins living in this part of Africa. One may speculate that the striking shine from the cleavage planes might have reminded the hominins of the shine of water in a puddle or a water hole. This could then have evoked a positive connotation between the optical effect and water, which is so essential for life and survival. One can also speculate that the ephemeral and intangible phenomenon of reflection might have been understood by the hominins as a kind of shining path into a transcendental world, and perhaps it was celebrated by unknown ritual acts. Interestingly, the attraction to shiny things seems to be innate for various animate beings, as it is found not only in infants but also in a number of animal species such as, for example, magpies.

Finally, I would like to return to Juanma’s plenary lecture at the IUCr Congress 2021 in Prague, in which he reported on the possible preferences of monkeys, and possibly infants, for regular and symmetrical patterns and his planned behavioral studies on them. For me, this will essentially be summed up in one question: is there an innate sense for symmetry? I have not found an answer myself, and I hope to get one from Juanma or other eminent experts. In doing so, I refer to two publications from the non-crystallographic literature in the strict sense. One was published in the German weekly DIE ZEIT on 9 June 2022 in an article by Christoph Drösser entitled Was ist leichter zu zählen? (What is easier to count?), where he reported on exciting debates between interested philosophers, psychologists, cultural anthropologists, cognitive researchers and other scientists. Ultimately, the question is whether there is an innate sense of numbers or whether the human understanding of numbers is a cultural achievement. It seems that the majority of these scientists think, and the article provides several examples to support this, that the sense of the natural numbers 1, 2, 3 and 4, maybe even 5, is innate, while everything else is in mathematics cultural appropriation (Menschenwerk), starting with the basic arithmetic calculation skills. Such an achievement can also be lost again if it is no longer needed. A recent example seems to me to be the widespread declining ability to do mental arithmetic, no doubt because of the ready availability of electronic devices.

Can the findings about innate number sense be transferred to symmetries? Is there possibly an innate sense of symmetry? To say it in advance, if there were such a thing, then this sense would not be equated with crystallographic symmetry concepts: the laborious learning of symmetry operations, plane, point or space groups and their complex relationships represents a cultural appropriation; through disuse one can lose this again. So there must be a more primal level from which one might hope to find something like an innate sense of symmetry.

In a chapter for Symmetry 2 – unifying human understanding (1989, edited by István Hargittai, Pergamon Press) Y.-M. Ha on pages 921–930 under the title Symmetry in pictures by young Chinese children describes the age-dependent development of the use of symmetry features in the paintings of Chinese children. The earliest recognizable symmetrical representations shown are observed in drawings by around 3-year-old children and can be interpreted as round, approximately radially-symmetric objects such as the sun or the silhouette of a human face. Later, these can be supplemented by mirror-symmetrically arranged eyes or ears, and stick figures with human-like attributes, such as outstretched arms and legs, also show mirror symmetry. The sequence of appearances of these early painted realizations of such patterns – and in later ages of even more complicated patterns – is certainly directed and controlled by the developmental process of the child’s brain and motor development. However, it should be clear that these are active pictorial formations by young children who have learned these skills, not original passive preferences for particular patterns presented to them. So is there in humans – and in hominins? – hidden, innate abilities to recognize symmetry? Y.-M. Ha does not report on such studies and the question remains unanswered for me.

However, it is worth noting an interesting cross-relationship between the accepted natural number sense mentioned before, on the one hand, and the cleaved rhombohedra of calcite found by the Ancient crystal collectors. The (idealized) rhombohedron, and also the cube from which the rhombohedron emerges through distortion, and provided that the respective polyhedron is non-transparent, as is the case with the corroded crystals of the find, the eye of the viewer perceives either 1, 2 or 3 crystal faces. Is it by pure chance? Or did the hominins attach a meaning to that? We do not know. With all due respect to the hominins, I presume that they tended more to number mysticism than to an early kind of Haüy’s theoretical approach. This question is open to various forms of speculation, which I would like to refrain from.

But what about the 4? Of course we don’t know either, but it doesn’t seem obvious how this natural number should be found on the cleaved rhombohedra of the calcites. But had later relatives of the `ancient crystal collectors' within the genus Hominidae lived in the canton of Berne in Switzerland, they might have seen a sight such as that depicted by the painter Ferdinand Hodler (1853–1918) in his painting Le Lac de Thoune aux reflets symétriques (1909). It shows an almost mirror-symmetrical mountain range reflected in the still waters of the lake, so the painter had to depict four `symmetrically equivalent' mountains. The reader may wonder what this means. Of course, this has little to do with calcite, but the peculiarity of the number 4 becomes apparent. This picture is shown as a present for my friend Juanma, in order to congratulate him once again on receiving the Liebau Prize.

[Figure2]Ferdinand Hodler (Berne,1853–Geneva, 1918) “Le Lac de Thoune aux reflets symétriques” (1909). Reproduction with permission of MAH Musée d'Art et d'Histoire, Geneva, Switzerland (Inventory No. 1939-0036).
3 December 2022

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