Mineralogy

The REE-Ti mineral chevkinite in comenditic magmas from Gran Canaria, Spain: a SYXRF-probe study

by Valentin Troll

Ferromanganese nodules and micro-hardgrounds associated with the Cadiz Contourite Channel (NE Atlantic): palaeoenvironmental records of fluid venting and bottom currents

by F. Javier González Sanz

González, F. J., Somoza, L., León, R., Medialdea, T., Torres, T., Ortiz, J. E., Lunar, R., Martínez-Frías, J., Merinero, R. 2012. Ferromanganese nodules and micro-hardgrounds associated with the Cadiz Contourite Channel (NE Atlantic): palaeoenvironmental records of fluid venting and bottom currents. Chemical Geology (doi:10.1016/j.chemgeo.2012.03.030)

Ferromanganese nodule fields and hardgrounds have recently been discovered in the Cadiz Contourite Channel in the Gulf... more Ferromanganese nodule fields and hardgrounds have recently been discovered in the Cadiz Contourite Channel in the Gulf of Cadiz (850–1000 m). This channel is part of a large contourite depositional system generated by the Mediterranean Outflow Water. Ferromanganese deposits linked to contourites are interesting tools for palaeoenviromental studies and show an increasing economic interest as potential mineral resources for base and strategic metals. We present a complete characterisation of these deposits based on submarine photographs and geophysical, petrographic, mineralogical and geochemical data. The genesis and growth of ferromanganese deposits, strongly enriched in Fe vs. Mn (av. 39% vs. 6%) in this
contourite depositional system result from the combination of hydrogenetic and diagenetic processes. The interaction of the Mediterranean OutflowWater with the continental margin has led to the formation of Late Pleistocene–Holocene ferromanganese mineral deposits, in parallel to the evolution of the contourite depositional system triggered by climatic and tectonic events. The diagenetic growth was fuelled by the anaerobic oxidation of thermogenic hydrocarbons (δ13CPDB=−20 to −37‰) and organic matter within the channel floor sediments, promoting the formation of Fe–Mn carbonate nodules. High 87Sr/86Sr isotopic values (up to 0.70993±0.00025) observed in the inner parts of nodules are related to the influence of radiogenic fluids fuelled by deep-seated fluid venting across the fault systems in the diapirs below the Cadiz Contourite Channel. Erosive action of the Mediterranean Outflow Water undercurrent could have exhumed the Fe–Mn carbonate nodules, especially in the glacial periods, when the lower core of the undercurrent was more active in the study area. The growth rate determined by 230Thexcess/232Th was 113±11 mm/Ma, supporting the hypothesis that the growth of the nodules records palaeoenvironmental changes during the last 70 ka. Ca-rich layers in the nodules could point to the interaction between the Mediterranean OutflowWater and the North Atlantic DeepWater during the Heinrich events. Siderite–rhodochrosite nodules exposed to the oxidising sea-bottom waters were replaced by Fe–Mn oxyhydroxides. Slow hydrogenetic growth of goethite from the seawaters is observed in the outermost parts of the exhumed nodules and hardgrounds, which show imprints of the Mediterranean Outflow Water with low 87Sr/86Sr isotopic values (down to 0.70693±0.00081). We propose a new genetic and evolutionary model for ferromanganese oxide nodules derived from ferromanganese carbonate nodules formed on continental margins above the carbonate compensation depth and dominated by hydrocarbon seepage structures and strong erosive action of bottom currents. We also compare and discuss the generation of ferromanganese deposits in the Cadiz Contourite Channel with that in other locations and suggest that our model can be applied to ferromanganiferous deposits in other contouritic systems affected by fluid venting.

A hitherto unrecognised band in the Raman spectra of silica rocks: influence of hydroxylated Si–O bonds (silanole) on the Raman moganite band in chalcedony and flint (SiO2)

by Patrick Schmidt

Patrick Schmidt, Ludovic Bellot-Gurlet, Aneta Slodczyk and François Fröhlich, 2012, Physics and Chemistry of Minerals, 39(6), 455-464.

Compositional variations in titanite

by Bart Kowallis

Kowallis, B.J., Christiansen, E.H., and Griffen, D.T., 1997, Compositional variations in titanite: Geological Society of America Abstracts with Programs, v. 29, p. A-402.

PDF 3D: Rosa del desierto - Desert rose (Morocco)

by Francisco José López Fraile

Realizado a partir de un escaneado láser.

El PDF 3D es un formato que soporta modelos de 3D y permite interactuar con ellos: mover, rotar, medir, extraer secciones, etc. Se necesita tener instalado el software Acrobat Reader (gratuito, mínimo versión 8).

“Weiß wie Schnee, rot wie Blut“. Naturwissenschaftliche Analysen zu weißen Einlagen in frühmittelalterlichen Granat-Schmuckstücken.

by Alexandra Hilgner

In: P. Jung / N. Schücker (Hrsg.), Utere felix vivas. Festschrift für Jürgen Oldenstein. Universitätsforschungen zur prähistorischen Archäologie, 208 (Bonn 2012) 77-92.

(In German)

Im frühen Mittelalter treten häufig granatverzierte Objekte mit Einlagen aus einem weißen bis grünbläulich... more
Im frühen Mittelalter treten häufig granatverzierte Objekte mit Einlagen aus einem weißen bis grünbläulich verfärbten Material auf, dem bisher in der Forschung relativ wenig Aufmerksamkeit geschenkt worden ist. Im vorliegenden Beitrag wird der aktuelle Wissensstand zusammengefasst und anhand einiger untersuchten Objekte erörtert, welche naturwissenschaftlichen Methoden zur Bestimmung dieser Einlagen geeignet scheinen. Neben einer kurzen Erläuterung der verschiedenen analytischen Methoden werden in diesem Beitrag auch die wichtigsten mineralischen Komponenten vorgestellt, die als Einlagenmaterial Verwendung finden können.


Abstract:
Archaeometric analyses of white inlays in early medieval garnet jewellery.


Garnet decorated objects in the early Middle Ages often have also inlays made from a white or whitish material, which is not well analyzed, yet. Using the example of several currently analyzed objects it is discussed which method seems most suitable. Different analytical methods are presented as well as the current state of knowledge and the most common mineral elements used as inlay material.

El cuarzo como material votivo y arquitectónico en el complejo funerario megalítico de Palacio III (Almadén de la Plata, Sevilla): Análisis contextual y mineralógico

by Leonardo García Sanjuán

The impact of malignant pleural mesothelioma throughout Italy in the years 1995/–2002: a geo-referenced study relating death rate to population distribution

by Federico Maria de Grisogono

Searching for Pedogenic Phyllosilicates in Ancient Soils on Mars

by Briony Horgan

Presented at the 2011 AGU Fall Meeting

On Earth, vast deposits rich in phyllosilicates are commonly created during soil formation, or pedogenesis. When soils... more On Earth, vast deposits rich in phyllosilicates are commonly created during soil formation, or pedogenesis. When soils are preserved in the stratigraphic record as paleosols, they become valuable resources for terrestrial geologists because paleosol isotopes, mineralogy, and chemical weathering profiles can be used to reconstruct ancient surface environments and to provide quantitative constraints on regional paleo-climate. Thus, paleosol sequences developed in sedimentary settings can record millions of years of surface and climatic evolution. Ancient paleosols on Earth also have excellent organic and biosignature preservation potential, and therefore harbor some of the oldest known (2-3 Ga) non-marine organics, biosignatures, and fossils.

On Mars, pedogenesis in the ancient past may be responsible for some of the phyllosilicate-bearing units observed today, especially for regionally extensive deposits and those in clear sedimentary settings (e.g., Arabia Terra/Mawrth Vallis, Gale Crater, Noctis Labyrinthus). Many of these possibly pedogenic deposits exhibit compositional layering (e.g., interbedded kaolinites, smectites, and sulfates), which may have formed due to episodic sediment deposition under changing environmental conditions. Such deposits represent excellent targets for in situ investigation, as finding and characterizing paleosols on Mars would allow us to place constraints on the extent and duration of past surface and near-surface habitability, and may even provide preserved samples of ancient martian organics.

We are currently investigating a broad range of methods for identifying and characterizing paleosols on Mars from orbit and in situ with Mars Science Laboratory, based on analysis of phyllosilicate-rich (30-95 wt.%) Eocene-Oligocene paleosols in the Painted Hills of the John Day Fossil Beds National Monument in Eastern Oregon. These paleosols were formed under a wide range of environmental conditions, and include highly weathered soils rich in well-crystalline oxides and kaolinites, moderately weathered soils rich in smectites, and minimally weathered soils rich in poorly-crystalline allophanes and ferrihydrite.

Here we present (1) an overview of the climatic regimes that lead to the pedogenesis of specific phyllosilicate minerals, (2) the near and mid-infrared spectral properties and interpreted mineral assemblages of these terrestrial paleosols, and (3) an evaluation of a pedogenic origin for phyllosilicates at several sites on Mars, including those listed above. Preliminary results from near-infrared spectral analysis of our terrestrial paleosols indicate that paleo-environment can be constrained based on mineral assemblages interpreted from spectral properties, including phyllosilicate composition (constrains water availability), the presence of allophane and ferrihydrite (indicating a cool climate), and the strength of oxide absorptions (constrains soil maturity). Mineral assemblages can also be used to detect burial diagenesis by the presence of diagenetic minerals, including celadonite, illite, and hematite (in the presence of phyllosilicates indicating less mature soils). Our results also indicate that poorly crystalline minerals (allophane and ferrihydrite) can be spectrally dominant in these soils even after burial and diagenesis.

Formation processes of methane-derived authigenic carbonates from the Gulf of Cadiz

by F. Javier González Sanz

Magalhães, V.H., Pinheiro, L.M., Ivanov, M.K., Kozlova, E., Blinova, V., Kolganova, J., Vasconcelos, C., McKenzie, J.A., Bernasconi, S.M., Kopf, A., Díaz-del-Río, V., González, F.J., Somoza, L. 2012. Formation processes of methane-derived authigenic carbonates from the Gulf of Cadiz. Sedimentary Geology 243-244, 155-168

The Gulf of Cadiz, NE Atlantic, represents an area of extensive formation of methane-derived authigenic carbonates... more The Gulf of Cadiz, NE Atlantic, represents an area of extensive formation of methane-derived authigenic carbonates (MDAC), indicative of fluid seepage. These MDAC, that reach extraordinary length and thickness, were geophysically mapped and sampled and the recovered carbonate-cemented material has δ13C values as low as −56.2‰ VPDB, indicating methane as the major carbon source. The MDAC form two main lithologic
groups, one mainly comprising dolomite and the second dominated by aragonite. The dolomite-dominated samples were found along fault-controlled diapiric ridges, on some mud volcanoes and mud diapirs, all on the pathway of the Mediterranean Outflow Water, and along fault scarps. Aragonite pavements were found associated with mud volcanoes and along fault scarps, but are otherwise not restricted to the pathways of
the Mediterranean Outflow Water. Based on the results from this study, we propose that the two lithologic groups reflect different geochemical formation environments associated with a formation model based on their morphology, mineralogy and geochemistry. The aragonite-dominated samples represent precipitation of authigenic carbonates at the sediment–seawater interface or close to it, in a high alkalinity environment resulting from anaerobic oxidation of methane-rich fluids venting into sulphate-bearing porewaters. In contrast, the dolomite-dominated samples result from cementation along fluid conduits inside the sedimentary column with a somewhat restricted seawater ventilation. The dolomite chimneys form in places presently
swept by the strong flow of the Mediterranean undercurrent so that the unconsolidated sediments are eroded and the chimneys are exposed at the seafloor. The widespread and large abundance of MDAC is a direct evidence of extensive methane seepage episodes in the Gulf of Cadiz. The coincidence of the different lithologic types in close spatial and temporal association indicates a persistence of seepage episodes in some
structures over large periods of time.

"Analisi storico-archeologica” and “Argomenti archeologici in favore di una provenienza locale della pietra”

by Andrea Babbi

in A. Babbi, G. Testa, M. Barbieri, S. Cancelliere, “Un vaso in pietra con immagine antropomorfa dalla necropoli delle Arcatelle di Tarquinia. Considerazioni storiche, archeologiche e mineralogiche”, in Miti, simboli e decorazioni, in Atti del VI Incontro di Studi di Preistoria e Protostoria in Etruria (Pitigliano 2002), CENTRO DI STUDI DI PREISTORIA E ARCHEOLOGIA - ONLUS, Milano 2004, 351-359

"Protohistorical artefacts made of alabaster” and “Data indicating the use of local alabaster”, in A. Babbi, G. Testa, M. Barbieri, S. Cancelliere, “Evidence of a protohistoric quarrying and carving of local alabaster in Tarquinia - Italy

by Andrea Babbi

in Communities and settlement from the Bronze Age to early medieval period. Proceedings of the 6th Conference of Italian Archaeology (Groningen 2003), in British Archaeological Reports International Series 1452 (I), HADRIAN BOOKS LTD, Oxford 2005, 506-512

The Permian Moradi Formation of northern Niger: Paleosol morphology, petrography and mineralogy

by J.Sébastien Steyer

Meteorites from the United Arab Emirates: Description, weathering, and terrestrial ages

by Heiko Kallweit

Mineralogy and mechanical properties of roofing slate: applications in the prospection and quarrying of slate deposits

by Remigio Paradelo

Engineering Geology (2010). Co-authored with V. Cárdenes, A. Rubio-Ordóñez, A. López-Munguira, R. de la Horra, C. Monterroso & L. Calleja.

The European norm UNE 12326 for roofing slate defines the mechanical properties of a slate tile through the Bending... more The European norm UNE 12326 for roofing slate defines the mechanical properties of a slate tile through the Bending Strength test, which defines the modulus of rupture (MoR) of the tile. This MoR is related to the durability of the slate, and is one of its main commercial quality properties. During the prospection task previous to open a new slate quarry, it is crucial to define the MoR. The Bending Strength test needs proper slate tiles and a flexion press. To supply these slate tiles it is frequently necessary to open experimental quarry fronts, which are very expensive, and do not guarantee the viability of the quarry. Therefore, a method which could reduce the costs and time for the mechanical characterization would be very useful. In this work we have tried to relate the MoR to the mineralogical and petrographic characteristics of slate, using the Petrographic Examination test, also part of UNE 12326. This test contemplates the finding of a numerical index called Mica Stacking Index (MSI) which quantifies the mica layers fabric. We collected fifteen samples of roofing slates from the Northwest of the Iberian Peninsula and we studied them by using the Bending Strength and Petrographic Examination tests, plus mineralogical quantification using X-ray diffraction and measure of the illite crystallinity (Kubler Index) to determine the metamorphic grade. We have found a strong positive correlation between MoR values and MSI, and a negative correlation between MoR and Mica percentages. These correlations may be used to deduce the MoR, reducing costs during the exploitation labours in roofing slate mining, and also can be used in the quality controls on a working slate quarry.

Passivation techniques to prevent corrosion of iron sulphides in roofing slates

by Remigio Paradelo

Corrosion Science (2009). Co-authored with V. Cárdenes & C. Monterroso.

The aim of the present study was to evaluate the efficacy of different methods of sulphide microencapsulation in terms... more The aim of the present study was to evaluate the efficacy of different methods of sulphide microencapsulation in terms of inhibiting sulphide oxidation in roofing slate. For this, a preliminary test was carried out with ground pyrite and the methods that provided the best results were applied to samples of roofing slate. Protection against oxidation was measured by the amount of iron released after enforced oxidation with H2O2 in the tests with pyrite, and by thermal cycle alteration, SO2 and saline spray tests (EN 12326-2:2000 and EN 14147:2004) in the tests with the slate samples. The results indicate that treatments with potassium phosphate and potassium silicate, proposed for controlling acid mine drainage, were the most effective at protecting pyrite against oxidation, and that these methods are also effective when applied to slate.

Geology, mineralogy, and geochemistry of granite-hosted gold telluride mineralization at Panormos Bay, Tinos Island, Greece.

by Dimitrios Zouzias

P G Spry, S F Tombros, St Seymour, K, A Williams-Jones, D Zouzias (2006) Geological Association of America v. 38, 4. pp. 55 GSA meeting in Akron Ohio, April, No. 4, p. 55 [Abstract in Program] 

Abstract: The largest low-sulfidation epithermal gold-telluride deposits in the world (e.g., Emperor, Fiji; Cripple... more Abstract: The largest low-sulfidation epithermal gold-telluride deposits in the world (e.g., Emperor, Fiji; Cripple Creek, U.S.A.) occur in intrusive volcanic rocks of alkaline or calc-alkaline affinity. By contrast, unexploited Au-Ag-Te mineralization at Panormos Bay, Greece, is relatively unusual in that it is genetically related to a F- and B-bearing granite (Tinos leucogranite). The Panormos Bay vein system, which is hosted in Miocene marbles, is composed primarily of thirty nearly parallel, high-angle quartz veins that extend for at least 500 m. In places, gold mineralization occurs in breccias. Zones of chlorite, talc, and muscovite-albite-tourmaline alteration, up to 50 cm wide, are associated with precious metal-bearing milky and clear quartz veins. The Au-Ag-Te mineralization is developed in stage V of eight hydrothermal stages. Stage V consists of three sub-stages (early, middle, and late) that are characterized by Ag-, Cu-, and Au-bearing tellurides, respectively. Hessite, sylvanite, altaite, native tellurium, stützite, and Cu-bearing cervelleite characterize the early stage whereas melonite, rickardite, vulcanite, weissite, and native tellurium are present in the middle stage. Late stage V contains rickardite, kostovite, krennerite, petzite, and calaverite. Fluid inclusion studies suggest that hydrothermal mineralization was deposited under hydrostatic pressures at a minimum depth of 1km from moderate-temperature (155o-321oC), low to moderately saline (0.2 to 6.3 equiv. wt % NaCl), effervescing, CO2-bearing fluids that contained appreciable amounts of CaCl2 and MgCl2. Calculated isotope compositions of δ18O = -3.3 to 5.1 per mil and δD of -73 to -62 per mil for waters in equilibrium with muscovite, quartz, and talc are consistent with ore fluids being derived from the Tinos granite that subsequently mixed with a more dilute, low temperature meteoric fluid. Calculated δ13CCO2 (-2.0 to -0.3 per mil) and δ34SH2S (-10.5 to 0.8 per mil) compositions of the ore fluids indicate an igneous source of carbon and sulfur, which were highly exchanged with a meta-sedimentary source. Epithermal gold mineralization at Panormos Bay is one of several granite-related gold occurrences (including nearby Apigania Bay) in Greece.

Tellurium-rich magmatic-hydrothermal systems in northeastern Hellas (Greece) and Cyclades Islands: a comparative study of ore mineralogy and physicochemical parameters.

by Dimitrios Zouzias

Tombros St, P Voudouris, K St Seymour, D Zouzias (2006) Geological Association of Canada - Mineralogical Association of Canada (GAC-MAC). May 14 to 17, 2006 Joint Annual Meeting Saskatoon, Montreal, v. 64, [Abstract in Program] 

Abstract: Au-Ag tellurides constitute a source of precious metal (second in line of importance for gold) and tellurium... more Abstract: Au-Ag tellurides constitute a source of precious metal (second in line of importance for gold) and tellurium extraction. In the 1950’s the sole use of Te was in the production of steel and wrought iron. However, with the evolution of electronics Te became a high-tech metal with applications such as in Cd-Te solar cells, photovoltaic media, Te-Se photocopying, infrared detectors and in non-linear optical systems. In Hellas (Greece), precious metal tellurides are hosted within Oligocene to Miocene magmatic systems as epithermal and porphyry occurrences of varying degrees of sulphidation in two areas: the Northeastern Hellenic and the Cyclades belts. In the Northeastern Hellenic belt the Servomacedonian-Rhodope metallogenic area hosts several major ore deposits of which St. Demetrios (260,000 tones at 3.5 gr/t Au) and Perama Hill (11 million tones at 3.71 gr/t Au) are the most promising for future exploration. Tellurides are the major carriers of gold also in Western Thrace in the epithermal to porphyry type mineralization in Santa Barbara, Mavrokoryfi and Pefka prospects. Lemnos island, immediately south of the North Anatolia Fault (NAF), represents the southward extension of this belt with the quartz stockwork of the Fakos gold telluride prospect which partakes of a shoshonitic monzonite porphyry system. In the Cyclades, unexploited Au-Ag mineralization at Panormos Bay, Tinos island, is genetically related to Miocene fluorine- and boron-bearing leucogranite. The vein system, which is hosted in Mesozoic marbles, is composed primarily of 30 nearly parallel quartz veins that extend for at least 500m. Gold mineralization occurs in breccias which are the products of carbofracturing related to CO2 effervescence of the ore fluid. The Au-Ag-Te mineralization is developed in Stage V of eight mesothermal to epithermal polymetallic stages which precipitated 71 ore and gangue minerals. Stage V consists of early, middle and late substages that are characterized by Ag-, Cu- and Au-bearing tellurides respectively. The Panormos polymetallic mineralization is low-sulphidation (LS), whilst the northeastern occurrences are HS-IS in character. Reconnaissance exploration for tellurides is presently underway in other parts of the Cycladic belt which are host to Miocene granitic intrusions. The geological and physicochemical conditions for Au-Ag telluride formation for the Northeastern Hellenic and Cyclades belts are compared in this work.

Floating sandstones off El Hierro (Canary Islands, Spain): the peculiar case of the October 2011 eruption

by Fiona Meade

roll, V. R., Klügel, A., Longpré, M.-A., Burchardt, S., Deegan, F. M., Carracedo, J. C., Wiesmaier, S., Kueppers, U., Dahren, B., Blythe, L. S., Hansteen, T., Freda, C., Budd, D. A., Jolis, E. M., Jonsson, E., Meade, F., Berg, S., Mancini, L., and Polacci, M. (2011)

The eruption that started off the south coast of El Hierro, Canary Islands, in October 2011 has emitted intriguing... more The eruption that started off the south coast of El Hierro, Canary Islands, in October 2011 has emitted intriguing eruption products found floating in the sea. These specimens appeared as floating volcanic "bombs" that have in the meantime been termed "restingolites" (after the close-by village of La Restinga) and exhibit cores of white and porous pumice-like material. Currently the nature and origin of these "floating stones" is vigorously debated among researchers, with important implications for the interpretation of the hazard potential of the ongoing eruption. The "restingolites" have been proposed to be either (i) juvenile high-silica magma (e.g. rhyolite), (ii) remelted magmatic material (trachyte), (iii) altered volcanic rock, or (iv) reheated hyaloclastites or zeolite from the submarine slopes of El Hierro. Here, we provide evidence that supports yet a different conclusion. We have collected and analysed the structure and composition of samples and compared the results to previous work on similar rocks found in the archipelago. Based on their high silica content, the lack of igneous trace element signatures, and the presence of remnant quartz crystals, jasper fragments and carbonate relicts, we conclude that "restingolites" are in fact xenoliths from pre-island sedimentary rocks that were picked up and heated by the ascending magma causing them to partially melt and vesiculate. They hence represent messengers from depth that help us to understand the interaction between ascending magma and crustal lithologies in the Canary Islands as well as in similar Atlantic islands that rest on sediment/covered ocean crust (e.g. Cape Verdes, Azores). The occurrence of these "restingolites" does therefore not indicate the presence of an explosive high-silica magma that is involved in the ongoing eruption.

Matrices, not seeds. Vallisneri’s research on mines: between empiricism and philosophy

by Francesco Luzzini

in History of Research in Mineral Resources, Proceedings of the INHIGEO Symposium in Madrid-Almadén-Iberian Pyritic Belt, Spain (July 5-10, 2010), edited by J.E. Ortiz, O. Puche, I. Rábano and L.F. Mazadiego, Madrid, Instituto Geológico y Minero de España, Cuadernos, del Musero Geominero, 13, 2011, pp. 105-112.

Since the beginning of his scientific activity the physician and naturalist Antonio Vallisneri (1661-1730) devoted... more Since the beginning of his scientific activity the physician and naturalist Antonio Vallisneri (1661-1730) devoted many studies to the Earth sciences. In those years his interest focused
particularly on the features of mineral kingdom and its relationship with spring water. The first observations date back to the last decade of XVII century, when the author analysed the gypsum and sulphur veins on the Monte Gesso, in the Duchy of Modena and Reggio.
Some years later, during one of his journeys across the northern Apennines in search for the origin of springs, Vallisneri reached the Este domain of Garfagnana. There he explored the iron caves of Fornovolasco: this experience allowed him to support his theory with many empirical information, later exposed in the Lezione Accademica intorno all’Origine delle Fontane (1715).
The many data collected by Vallisneri encouraged him to outline a theoretical interpretation of mineral genesis. He supposed the mineral veins as developed by ‘seeds’ released in the Earth by God. The successful growth of ore veins, therefore, depended on the more or less favourable environment they would have found by accident. These ‘seeds’, as the author clarified, were not intended to be the very same of ‘perfect germs of generation’ typical of animals or plants. Rather, they were ‘matrices’ that had to be detected in order to exploit the wealth of mines posed, in a proper Leibnizian conception, ‘by God for world’s use’.