Ornamental Stone Research Articles

Ranking the sawability of ornamental stone using Fuzzy Delphi and multi-criteria decision-making techniques

The main purpose of this study is to compare the many different rock properties in the rock sawability. The comparison was realized with the combination of the analytic hierarchy process (AHP) and Fuzzy Delphi method and also TOPSIS method. The analysis is one of the multi-criteria techniques providing useful support in selecting among several alternatives with different objectives and criteria. FDAHP method was used in determining the weights of the criteria by decision makers and then ranking the sawability of the rocks was determined by TOPSIS method. The study was supported by the results obtained from a questionnaire carried out to know the opinions of the experts in this subject. During the research process, the rock sawability was evaluated in terms of production rate of sawn rock. Prediction of production rate is important in the cost estimation and the planning of the stone plants. The new developed ranking method may be used for evaluating production rate of ornamental stone at any stone factory with different stone. Some factors such as uniaxial compressive strength, Schmiazek F-abrasivity, mohs hardness and Young’s modulus must be obtained for the best production rate ranking.

Study on Serpentinites and the Consequence of the Misuse of Natural Stone in Buildings for Construction

AbstractSome rocks are very attractive as ornamental stone, but not all of them accomplish the needed requirements to be used in construction. Serpentinite can be an appealing rock, very commonly used as dimension stone. However, not all serpentinites can be used in such a way. The most widely used commercial serpentinite comes from Pakistan and India (i.e., Rajasthan Green), but other countries also produce serpentinites, such as Italy (Verde Alpi, Verde Polcevera, Verde Prato), United States (Vermont Verde Antique), and Spain (Verde Macael, Verde Pirineos). The geomechanical properties of a serpentinite are strongly related to its mineralogy (serpentine-group minerals and carbonates, mostly), and not all serpentinites are created equal. We have compared the mineralogy and mechanical properties of serpentinites that comply with the Standard Specification for Serpentinite as Dimension Stone (i.e., Rajasthan Green, Verde Macael) with those that do not (Verde Pirineos). Verde Pirineos consists of lizardite,...

Effect of Ornamental Rock Sludge on the Strength and Densification of Cement Pavement Blocks

The city of Cachoeiro de Itapemirim, in the southwest of Brazil, has a large industrial activity related to the extraction of ornamental stones. This brings jobs and income to the state of Espirito Santo but also cause problems due to the discard of the sludge resulting from the stone processing operations (SPO). The reuse of this SPO in construction materials such as plaster and bricks has been proposed as an alternative to reduce its environmental impact. This work evaluates another low cost alternative based on the incorporation of the SPO in the fabrication of cement pavement blocks. Using an experimental planning method, the mixture of sand, gravel and SPO, jointly with a water/cement proportion, was investigated for the method surface response. Based on this statistical method, pavement blocks with an apparent density of 1.96 g/cm3were found for incorporation in the range of 10 to 34%.

Influence of the Granite Waste into a Clayey Ceramic Body for Rustic Wall Tiles

This work has as its objective to evaluate the influence of a granite waste into a clayey ceramic body for obtaining of rustic wall tiles. As raw materials, a clayey ceramic body for red ceramic production and a granite waste, resulting from ornamental stones cutting with the multi-wire technology were used. Compositions using 0, 10, 20 and 30% of waste incorporated into ceramic body were prepared. Specimens were fabricated by uniaxial press-molding at 20 MPa and sintered at 1050°C. The following properties were determined: linear shrinkage, water absorption and flexural rupture strength. In general, within the error bar, there was no influence of the waste in the values of water absorption of the clayey ceramic body. The results showed that all investigated formulations used in this work for the production of rustic wall tiles attend the standards for water absorption and mechanical strength.

Discrete Simulation of the Infrastructure for Diamond Embedded Metallic Saw Production

Diamond embedded cutting saws (DCSs) are basic tools commonly used in every ornamental stone processing operation from the extraction of the quarry block to the finishing of tiles. Diamond particles are the hard and abrasive essential component that has to be well adhered to the saw matrix, whether metallic, ceramic or polymeric. This work presents a computer simulation analysis and experimental design for an optimized manufacturing process of DCSs. This discrete simulation assesses the basic parameters involved in a possible industrial production in order to maximize the dynamics of the system and operational rules needed for best final products.

Analysis of the surface of different marbles by X-ray photoelectron spectroscopy (XPS) to evaluate decay by SO2 attack

Atmospheric pollution is one of the main agents of decay in monuments and other works of art located in industrialised urban centres. SO2 is a permanent and abundant component of air pollution and, although it does not have an immediate visual effect, after continuous exposure, it can cause irreversible damage to building materials. Marble is one of the most commonly used ornamental stones in historical monuments and its mineralogical composition makes it very susceptible to damage caused by exposure to SO2. To measure the chemical reactions caused on marble by the action of atmosphere rich in SO2, selected calcitic and dolomitic samples were altered by weathering accelerated test. For this, seven marble types (four calcitic and three dolomitic) were exposed to high concentration of sulphur dioxide for 24 h in a climate chamber under controlled temperature and humidity conditions (20 °C and > 90 % HR). Changes on marble surfaces caused by reactions of SO2 with calcite and dolomite were studied using two non-destructive techniques: chromatic change by means of colorimetry and chemical analysis using X-ray photoelectron spectroscopy (XPS). The development of new mineral phases was also observed by scanning electron microscopy. Colorimetric analysis revealed a decrease in lightness and chromatic parameters suggesting that these changes were due to the development of new mineral phases in all marbles. The XPS technique, which is generally used in the analysis of metals, is relatively new in the field of stone deterioration. It enabled us to recognise the development of sulphites and sulphates on marble surfaces with high precision, after just 24 h of exposure to high SO2 concentrations and to distinguish different decay paths for calcitic and dolomitic marbles.

Serpentinite

Serpentinites are metamorphic rocks formed from the alteration of ultramafic igneous rocks. Their precursors largely consist of clinopyroxene, orthopyroxene, olivine and a member of the spinel group, along with other accessory minerals. Serpentinization can be produced through the percolation of fluids of different origins. The transformation gives rise to other rocks, serpentinites, that are characterized by a high‐water content mineralogy (serpentine) and, sometimes, remnants of the original phases. However, serpentinites may also undergo a subsequent carbonation process, transforming most of the mineral phases into carbonates. This is why confusion may arise when dealing with these rocks in the industrial sector, where geologists are not often involved. Serpentinites are often found in natural stone catalogues under the name of ‘green marble’ and this can be misinterpreted by builders and architects, causing misuse of this rock as an ornamental stone.

Evaluation of Turkish black amber: A case study of Oltu (Erzurum), NE Turkey

Turkish black amber named OltutaAŸi in Turkish is one of the best examples of semi-precious stone to be found in the world. It is mainly extracted in the county of Oltu (Erzurum) and surrounding mountains, NE Turkey since the 18th century. At the present time, it is known as ornamental stone and its rosary is very famous worldwide. However, there is no modern review of geological properties of the OltutaAŸi and OltutaAŸi-bearing deposits. This paper filling this gap presents the results of original research on the subject. The OltutaAŸi-bearing deposit with Jurassic-Cretaceous is a flych-character sequence, including limestone, sandstone interbedded with volcanic, sandstone, marl and claystone levels. The OltutaAŸi is seen asobserved in the a form of lenses with 0.2 to 75 mm in thick within the OltutaAŸi-bearing geological material represented by pebble-sandstone-siltstone alternation, including sandy-claystone and marl levels. These lenses present the folded and faulted structures in parallel with the maincounty rocks due to the tectonic deformation affecting the region. It is seenobserves from microphotographs that OltutaAŸi includes dominantly consists of carboncarnone and it includes has fracture filled with resinite and maceral such as fusinite and semifusinite. Also, it is possible to observethere are that euhedral pyrite and hematite minerals generally finely disseminatedin the OltutaAŸi organic matter. Key words: Oltu, OltutaAŸi, Turkish black amber, Jurassic-Cretaceous flysch, semi-precious stone.

Mineralogical and radioactive properties of some Egyptian granitoid rocks and their suitability for ornamental stones

Granitoid rocks are widely distributed all over the Egyptian Shield, constituting approximately 60% of its plutonic assemblage. Granitoid ornamental stones could be commercially defined as a visibly granular, igneous rocks ranging in color from pink to light or dark grey. Detailed mineralogical composition was investigated by using polarizing microscope (Olympus BX50, Japan) and X-ray diffraction (XRD) X-ray model X’ Pert ProPhillips MPD PW 3050/60 X-ray diffractometer. Radiometric measurement is recommended before utilizing the decoration stones which could be used in different purposes of construction especially indoor purposes. Twelve selected representative samples from some Egyptian granitoids rocks were examined by using Inductive Coupled Plasma Mass Spectrometer (ICP-MS) in Acme Analytical labs, Canada. The measured values were in ppm and would be transformed to Bq/kg which normally used to measure it in construction or building materials. Based on radiation measurement of (U and Th) for the studied granitoids of Gabal Shawab and Gabal Abu Shieh El-Atshan granites lie within the world-wide safety limits of constructing building materials, while Gabal El-Sibai and Gabal Homrit El-Gergab granites not realize these safety requirements. Homrit El-Gergab granitoids represented the highest concentration of the studied granitoids while Gabal Shawab represented the lowest one. Ornamental stones of G. Shawab and Wadi Abu Shieh El-Atshan are suitable for all construction weather indoor or outdoor decoration purposes.

Geometrical design of ornamental stone slabs cutting using the neutral region concept

This paper presents a study of the geometrical design of optimum cutting shapes in granite or marble slabs with the aim of improving cutting operations and reducing tailings in ornamental stone sawshops. To do so, a theory is developed to determine the neutral region of a planar domain using polygonal balls. The neutral region of a planar domain is defined on the basis of geometrical concepts such as the oriented directional distance, the polygonal ball and equidistance with respect to a polygonal ball. Starting out from said neutral region, a polygonal pattern of maximum area may be situated within the polygonal boundary that delimits the ornamental stone. A computational algorithm is implemented to solve this problem is presented, along with some practical examples of cutting granite slabs to validate the theory developed here.

A radiological study of some ornamental stones: the bluish granites from Extremadura (Spain)

Abstract. In the area of Trujillo (Extremadura, Spain) we have found a variety of striking bluish and secondary yellow granites outcropping within the Plasenzuela pluton. They are all quarried under different names and are characterized by leucocratic minerals in which a bluish phosphate is dispersed throughout the rock. Their physical and mechanical properties make these granites a perfect option for most applications as ornamental rocks. Within the pluton the radiological background is fairly homogeneous, with no significant differences between the gamma ray fluxes of the different facies. U (6.4 ± 0.51 ppm), Th (2.9 ± 0.47 ppm) and K2O (4.32 ± 0.26%) contents determined in the laboratory by gamma-ray spectrometry from representative samples are in good accordance with fast in situ measurements carried out with the same technique and also with conventional chemical analysis. Estimated activities for K-40, Ra-226 and Th-232 were, on average, 1022 ± 36 Bq kg−1, 84 ± 9 Bq kg−1 and 6.8 ± 1.6 Bq kg−1. On the basis of these results, the I index of EU technical document 112 was determined, with an average result of 0.66 ± 0.03. This suggests that the rock can be used with no restrictions for all types of construction purposes. Striking differences were observed between the blue facies and the yellow facies in radon exhalation tests from crushed material (0.03 Bq kg−1 vs. 0.20 Bq kg−1). Since both granites have similar uranium contents (6.3 ppm and 6.5 ppm, respectively), these results can probably be explained in terms of important differences in the mineralogical distribution of this chemical element, radon emanation being enhanced in the yellow facies. However, due to the ordinary use as ornamental stone, the yellow facies does not present a radiological risk in terms of excess effective dose due to internal exposure to radon.

Características químicas dos resíduos de serragem segregados de rochas ornamentais do estado do Espírito Santo

Chemical characteristics of sawing waste segregated of ornamental stones from Espírito Santo state. Although there are several studies suggesting the use of ornamental rocks tailing for the manufacture of tiles, bricks, tiles, among others, of large application in Construction, none of them until this moment has presented satisfactory and systematic studies of sludge residual chemical characterization. Such industrial waste of ornamental stones is highlighted due to the enormous environmental and visual impacts generated, because large volumes of material are generated daily in the sawdust of stone blocks. For the management of waste, the characterization is considered the most important stage and the one that guides attitudes to be taken in assigning the same. This work sought the provision of subsidies for the inorganic chemistry characterization of the sawing waste sector from ornamental stones from the Espírito Santo state, starting from a sampling segregated, commercial type of rock, which consisted in the collection of samples directly in the discarding of handlooms sawdust, after the passage of sludge by a hydrocyclone and, therefore, before being mixed in the effluent tank. For each collected sample, in the laboratory, pH values, moisture content, humid and dried solid contents, and metal content of environmental interest were obtained. In the determination of metal levels, AAS, F AAS and GF AAS analytical techniques were used, which indicated good correlations between Fe and total Ca and between total Cr and original pH. Furthermore, high pH values, resulting from the excess of lime used in industrial production, were detected for some wastes, showing, for some materials, a type classification of «Class I» - hazardous waste. The average moisture content of 44.3%, with 13% standard deviation, indicates that using water in the industry must be sustained further, but this appears to be a uniform consumption. This paper has suggested, as to the process of sawing blocks of stone, according to the obtained results, that it starts periodically monitoring industrial wastes for the pH and toxic metals levels parameters.

Application of preliminary risk analysis at marble finishing plants in Recife’s metropolitan area

The finishing of marble occurs in quarries all over Brazil, being the most significant dimension of the ornamental stone sector, with 7,000 businesses. Recife's Metropolitan Area (RMR) contains approximately 106 marble quarries, 25 of them unionized. The study focused on the application of Preliminary Risk Analysis, conducted at two unionized quarries: M1, a small business; and the second, M2, considered a micro enterprise. In this analysis both the administrative and the productive sectors were evaluated. The fieldwork was done in the month of December 2010. The study revealed that the two quarries carried moderate risks in the administrative sector, mainly due to ergonomic factors, and that in the productive sectors the risks were high, specifically because of excess noise, dust material, and precarious electrical installations. Using the results of the qualitative analysis as a base, the need for quantitative study presents itself in order to determine the most adequate modes of protection to be of assistance in the management of these risks, guaranteeing the safety and health of the worker and consequently the improvement in productivity in this sector.

LA DECORACIÓN ARQUITECTÓNICA DEL CAMPAMENTO DE LA LEGIO VII GEMINA EN LEÓN

Summary The study of the fragments of ornamental stones found in the archaeological interventions developed in Leon, allows us to draw some conclusions about the architectural ornament in the camp of the legio VII gemina, paying the special attention to the archaeological and topographical context of the finds. While we may assume that the Roman camps have a rather impoverished monumental appearance, a closer investigation on the singles findspots of columns, wall piers, friezes and marble cladding confirm the existence of monumental buildings, some of them highly-decorated (baths, headquarters). This becomes a monumental expression of imperial power, expressed through the military architecture of one of the main settlements of the Roman army in Hispania during the Principate.

STUDY OF DURABILITY OF ALABASTER USED IN THE TEMPLES OF LUXOR AND KARNAK AND LABORATORY EVALUATION OF CONSOLIDATION TREATMENT

Alabaster is an ornamental stone that was widely used in ancient Egypt and it had a lot ofdeterioration factors. The present paper deals with two types of alabaster that located at WadiSannur and Wadi El Assuity, and their durability and geotechnical characteristics. Thesecharacteristics were examined before and after artificial ageing using simple analytical methods.Physical and mechanical properties were carried out on samples from quarries providing eachtype and the same samples were then exposed to artificial ageing with sodium chloride andheat which effectively produced deterioration comparable with that in Luxor and Karnaktemples. The results were tested on different alabaster objects from Luxor and Karnak templeswhere the use of alabaster. The study was also aimed to evaluate the efficiency of the variouscommercial silane-based and acrylic products in laboratory in order to recommend theprotective treatment for the conservative treatment of the alabaster. To fulfill this goal a soakingcharacterization and accelerated ageing tests were performed. Quite satisfying results havebeen observed, except for the original color of the alabaster samples and for particular conditionof application.

Potential thermal expansion of calcitic and dolomitic marbles from Andalusia (Spain)

Marble has historically been used as an ornamental stone because of its aesthetic appeal, ease of polishing and ex;cellent physical properties. One of the main factors affecting the durability of marbles is their thermal behaviour. Although marble is used extensively in Spain as a building and decorative material, little research has been done into its thermal behaviour. In this work, the textural and microstructural properties of seven calcitic and dolomitic marbles from Andalusia (southern Spain) were characterized to assess how these properties affect their thermal response. Rock fabric properties (grain morphology, boundaries and micro-crack populations) were studied by polarized microscopy and lattice preferred orientation using X-ray texture goniometry. Elastic properties were measured by ultrasound, thermal properties were determined by a six-rod dilatometer (thermal expansion) and the opening of micro-cracks was observed using environmental scanning electron microscopy. For each marble, thermal coefficients of calcite and dolomite crystals were calculated using thermo-X-ray diffraction, a novel application to characterize historic marbles. The results show that marble thermal expansion coefficients are related to preferred crystallographic orientation, which can help to identify the directions along which decay occurs. The results also show for the first time that the thermal expansion coefficient of the main components of marble,i.e.calcite and dolomite, is specific to each marble, and plays a key role in their different thermal behaviours. Thermal properties also depend on mineral composition, the existence of micro-cracks and hydric properties.

Sawability ranking of carbonate rock using fuzzy analytical hierarchy process and TOPSIS approaches

The aim of this paper is developing a new hierarchical model to evaluate and rank the sawability (power consumption) of carbonate rock with the use of effective and major criteria, and simultaneously taking subjective judgments of decision makers into consideration. The proposed approach is based on the combination of Fuzzy Analytic Hierarchy Process (FAHP) method with TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) methods. FAHP is used for determining the weights of the criteria by decision makers, and then rankings of carbonate rocks are determined by TOPSIS. The proposed method is applied for Iranian ornamental stone to evaluate the power consumption in rock sawing process. A variety of two groups of carbonate rocks (7 types) were sawn, using a fully-instrumented laboratory cutting rig at different feed rate (200, 300, 400cmmin−1) at constant peripheral speed (1770rpm) and depth of cut (35mm). During the sawing trials, the ampere and power consumption were monitored and calculated as performance characteristics of the saws. The results of the sawing trials (power consumption) were used to verify the result of the applied approach for ranking the carbonate rock sawability. It was concluded that the sawability of carbonate rocks can reliably be ranked, using the developed approach.

Molecular monitoring of the microbial dynamics occurring on historical limestone buildings during and after the in situ application of different bio-consolidation treatments

Microbially Induced Carbonate Precipitation is proposed as an environmentally friendly method to protect decayed ornamental stone and introduced in the field of preservation of Cultural Heritage. Recent conservation studies performed under laboratory conditions on non-sterile calcarenite stones have successfully reported on the application of a suitable nutritional solution, inoculated and non-inoculated with Myxococcus xanthus, as a bioconsolidation treatment. Furthermore, this procedure has been applied in situ, very recently, to selected historical buildings in Granada, Spain. For the first time, we evaluate the efficiency and risks of the in situ application of the above mentioned treatments onto two historical buildings in Granada. The evaluation consists of a detailed investigation of the micro-biota actively growing during the seven days of the treatments – short-term monitoring and of that remaining on the stones after six and twelve months of the application – long-term monitoring. A molecular strategy, including DNA extraction, PCR amplification of 16S rRNA sequences, construction of clone libraries and fingerprinting by DGGE (Denaturing Gradient Gel Electrophoresis) analysis followed by sequencing was used to gain insight into the microbial diversity present on the differentially treated stones. The monitoring of M. xanthus was performed by PCR using species-specific primers. Similar dynamics were triggered on both buildings by the application of the nutritional solution (inoculated or non-inoculated). 16S rDNA sequencing revealed the dominant occurrence of members belonging to the Firmicutes and Proteobacteria during the seven days of the treatment, whereas after one year the order Bacillales of the phylum Firmicutes was the predominantly detected microorganisms. M. xanthus could be detected only during the seven days of the treatment. The treatments seem to activate no dangerous microorganisms and furthermore, to select the remainder of a homogeneous group of carbonatogenic bacteria on the stones after a long period of time.

Natural radioactivity in ornamental stones: an approach to its study using stones from Iberia

Natural stones are commonly used both for interior and exterior construction but due to their mineralogy, some rocks (e.g., granite) can generate a high amount of radon in the atmosphere. Several samples of commercial ornamental stones from Iberia were analyzed for radon. A correlation between natural radioactivity, mineralogy and geochemistry provides a useful indication of the possible hazards of using such rocks indoors. A high radon content in a rock should lead to both restrictions for its use as interior building stone and, if it has been used, implementation of a ventilation system to reduce any hazard. Such rocks as serpentinite, which do not seem to present any problem related to natural radioactivity, are recommended for interior use in preference to granitic rocks.

Natural radionuclides content and radiological hazard of commercial ornamental stones: An integrated radiometric and mineralogical-petrographic study

Abstract Twenty samples of natural building materials commonly employed as ornamental stones in the international market have been investigated for natural radioactivity. External (gamma), as defined and used by the European Commission, and internal (alpha) hazard indexes were calculated and radon specific exhalation rate and emanation fraction were measured. The radiological investigation was complemented by an integrated mineralogical-petrographic and rock characterization approach. The most common radioactive accessory minerals occurring in the investigated samples are apatite, zircon and allanite, with minor monazite, thorite, thorianite, REE and Zr-oxides. Significant correlations with total activity concentration have been observed for K 2 O, Th and Ce concentrations. The emanation fraction is also influenced by both total porosity and porosity distribution. Radon exhalation rate and emanation fraction are very variable ranging from 0.0011 to 0.64 Bq kg −1 h −1 and from 0.2 to 62%, respectively. Most of the materials have radiological hazard indexes that do not exceed the European Commission limit values when used as ornamental or paving or flooring stones. However, three volcanic (Tufo Giallo Riano, Tufo Grigio Riano and Peperino Viterbese) samples could cause significant exposure both from excess radon indoor concentration (>200 Bq m 3 ) and from gamma radiation (>1 mSv y −1 ) when used as structural materials. This study further indicates that limit values for hazard indexes based on natural activity concentration and Rn emanation should take into account the lithological properties and use of the materials.