During a reorganization of the mineralogical collection of Turin University, old samples of the so-called <i>mohsite</i> of Colomba were found. “Mohsite” was discredited in 1979 by Kelly et al., as a result of some analyses performed on the equivalent material coming from the French region of Hautes-Alpes, but the original samples found in similar geological setting in Italy were lost and never analysed with modern equipment. After more than a century, the rediscovered samples of Professor Colomba were analysed by means of SEM-EDS analysis, microRaman spectroscopy, and X-ray diffraction. The results have demonstrated that the historical samples studied by Colomba are Pb-free dessauite-(Y), and pointed to an idealized crystal chemical formula (Sr<sub>0.70</sub>Na<sub>0.25</sub>Ca<sub>0.09</sub>)<sub>Σ=1.04 </sub>(Y<sub>0.62</sub>U<sub>0.18</sub>Yb<sub>0.09</sub>Sc<sub>0.08</sub>)<sub>Σ=0.97</sub>  <svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-4.58821pt;width:29.6625px;" id="M1" height="19.924999" version="1.1" viewBox="0 0 29.6625 19.924999" width="29.6625">
	
		
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</svg>(Ti<sub>12.66</sub><svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-4.78133pt;width:69.237503px;" id="M2" height="20.0625" version="1.1" viewBox="0 0 69.237503 20.0625" width="69.237503">
	
		
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</svg>)<sub>Σ=17.70</sub>O<sub>38</sub> and unit-cell parameters <i>a</i> = 10.376(3) Å, <i>c</i> = 20.903(6) Å, and <i>V</i> = 1949(1) Å<sup>3</sup>.

Erica Bittarello

Marco E. Ciriotti

Emanuele Costa

Lorenzo Mariano Gallo

&#x201C;Mohsite&#x201D; of Colomba: Identification as Dessauite-(Y)

Nepheline syenite ore is an essential constituent in ceramics and glass raw material meals, as a flux and as a source of alumina. The natural nepheline syenite rocks contain some undesired minerals, which are usually eliminated or reduced to the allowable limits by beneficiation. The present paper is concerned with characterization and beneficiation of an Egyptian nepheline syenite rock, at Abu Khruq locality, Eastern Desert, Egypt. The ore is exceptionally hard, with high crushing strength of 875&#x2009;kg/cm<sup>2</sup>, and iron oxide content of about 6.5&#x25;. The grain size of the constituents is relatively large. In some samples, the iron oxides are disseminated within the feldspars and nepheline syenite crystals, or in cracks and fissures within the feldspars crystals. The rock contains some environmental hazardous elements such as uranium, thorium, and radon. Magnetic separation and flotation techniques were applied, separately or in combination. Under optimum operating conditions, magnetic separation followed by reverse anionic flotation gave a concentrate assaying 0.2&#x25; Fe<sub>2</sub>O<sub>3</sub> and about 24&#x25; Al<sub>2</sub>O<sub>3</sub> at alumina recovery of about 80&#x25;. The radioactive elements were reduced in the concentrate to lower levels than their levels in the original rock.

Abdel-Zaher M. Abouzeid

Abdel-Tawab A. Negm

Characterization and Beneficiation of an Egyptian Nepheline Syenite Ore

The metamorphic rocks outcropping in the Western Alps are characterised by a great variety of white marbles which have been used since the antiquity. This variety mostly includes nine historical Piedmont white marbles (Ornavasso, Candoglia, Crevola, Pont Canavese, Foresto, Chianocco, Prali, Brossasco, and Garessio marbles) coming from well-known quarry sites and belonging to different metamorphic geological units of the Western Alps. The petrographical, minerochemical, and C&#x2013;O isotopic data of these white marbles have been integrated with CaO and trace element (Fe, Mn, and Sr) concentration determined on single crystals of carbonate minerals (i.e., calcite and/or dolomite) by means of a bench-to-top &#xb5;-XRF spectrometer. Principal component analysis and hierarchical cluster analysis were performed on a data set of 178 observations containing CaO, Fe, Mn, and Sr concentration as well as the maximum grain size (MGS), <i>&#x3b4;</i><sup>18</sup>O and <i>&#x3b4;</i><sup>13</sup>C. The use of only five selected variables (CaO, Fe, Mn, Sr, and <i>&#x3b4;</i><sup>18</sup>O) has provided the correct allocation of each individual observation to its relevant class. Therefore, this approach based mostly on a noninvasive &#xb5;-XRF determination will be useful to define the provenance of unknown marbles of alpine origin used in antiquity for cultural heritage.

Gloria Vaggelli

Margherita Serra

Roberto Cossio

Alessandro Borghi

A New Approach for Provenance Studies of Archaeological Finds: Inferences from Trace Elements in Carbonate Minerals of Alpine White Marbles by a Bench-to-Top <i>&#x3bc;</i>-XRF Spectrometer

Metamorphic florencite is being reported from kyanite-rich rocks from the eastern part of the Palaeo- to Mesoproterozoic Singhbhum shear zone. This is the first report of florencite from the Precambrian rocks of the Indian Shield. Host rock of florencite is a kyanite-rich rock (&gt;80
 vol%) with small and variable amounts of quartz, lazulite, augelite, and rutile. Florencite forms small (&lt;20 microns) idioblastic-to-subhedral crystals that are included in large kyanite grains. Rarely, florencite replaces kyanite. The florencite has small proportion of crandallite (8.7–11.8 mol%) and goyazite (&lt;2 mol%) components. Florencite of this study is dominated by Ce (~49 mol%) with significant La (~30 mol%) and Nd (~21 mol%). Compared to other florencite occurrences of the world, florencite of the studied rock is impoverished in S, Sr, and Ba and rich in P. 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Integrating all the geological features it is postulated that florencite was formed due to metasomatism of some aluminous protolith by infiltration of acidic fluids charged with <svg style="vertical-align:-3.276pt;width:42.049999px;" id="M4" height="19.924999" version="1.1" viewBox="0 0 42.049999 19.924999" width="42.049999" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"><g transform="matrix(.017,-0,0,-.017,.062,15.775)"><path id="x50" d="M46 650h247q112 0 169 -41q64 -49 64 -141q0 -91 -56.5 -143t-138.5 -62q-23 -3 -45 -1l-74 19v-157q0 -63 15.5 -77t83.5 -19v-28h-271v28q60 5 74 20t14 77v400q0 65 -12.5 79t-69.5 18v28zM212 559v-245q31 -12 73 -12q59 0 102 38t43 124q0 77 -42.5 115.5&#xA;t-108.5 38.5q-44 0 -56 -12q-11 -8 -11 -47z" /></g><g transform="matrix(.017,-0,0,-.017,9.633,15.775)"><path id="x4F" d="M381 665q131 0 226.5 -93t95.5 -239q0 -158 -96 -253t-238 -95q-137 0 -231 95t-94 238q0 142 92.5 244.5t244.5 102.5zM359 629q-89 0 -151 -74.5t-62 -208.5q0 -141 69 -233t175 -92q90 0 150.5 74t60.5 211q0 152 -69 237.5t-173 85.5z" /></g><g transform="matrix(.012,-0,0,-.012,22.325,19.863)"><use xlink:href="#x34" /></g><g transform="matrix(.012,-0,0,-.012,28.663,7.612)"><path id="x2212" d="M535 230h-483v50h483v-50z" /></g><g transform="matrix(.012,-0,0,-.012,35.647,7.612)"><use xlink:href="#x33" /></g></svg> and LREE.

Maitrayee Chakraborty

Sayan Biswas

Nandini Sengupta

Pulak Sengupta

First Report of Florencite from the Singhbhum Shear Zone of the East Indian Craton

A honey-yellow hydroxylclinohumite from ruby-bearing marbles of the Luc Yen district in northern Vietnam was characterized by electron microprobe (EPMA), single-crystal X-ray diffraction (XRD), micro-Raman, and Fourier-transform infrared (FTIR) spectroscopy. The studied crystals correspond to nearly ideal clinohumite with the structural formula 4[Mg<sub>2</sub>SiO<sub>4</sub>]<svg style="vertical-align:-0.0pt;width:4px;" id="M1" height="5.4499998" version="1.1" viewBox="0 0 4 5.4499998" width="4" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"><g transform="matrix(.017,-0,0,-.017,.062,5.388)"><path id="x22C5" d="M170 255q0 -25 -16 -41t-40 -16t-40 16t-16 41t16 41.5t40 16.5t40 -16.5t16 -41.5z" /></g></svg>[(Mg,Fe,Ti)(OH,F)<sub>2</sub>] and roughly equal F and OH proportions. Crystal structure analysis showed Ti substitution for Mg only at the Mg3 site. A Fourier-difference map revealed one hydrogen site associated with ninth oxygen atom. The calculated O–H bond distance was shorter than that in other natural clinohumites. FTIR revealed bands corresponding to combination of OH-stretching with Mg–OH and/or Fe–OH bending modes, combinations of OH<sup>−</sup> and Fe–OH vibrations, combination of fundamental bands of the Si–OH bonding, combination of OH<sup>−</sup> and Si–OH vibrations, and first (2<svg style="vertical-align:-3.25792pt;width:27.6875px;" id="M2" height="12" version="1.1" viewBox="0 0 27.6875 12" width="27.6875" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"><g transform="matrix(.017,-0,0,-.017,.062,7.675)"><path id="x1D708" d="M509 373q0 -52 -42.5 -118.5t-124.5 -159.5l-94 -107h-27q-22 209 -78 342q-21 48 -41 48q-18 0 -63 -62l-22 21q77 111 125 111q30 0 52 -21.5t38 -75.5q37 -130 52 -285q48 62 74.5 99.5t53.5 87t27 76.5q0 43 -17 60q-5 5 -5 15q0 17 12.5 30.5t28.5 13.5&#xA;q21 0 36 -22.5t15 -52.5z" /></g><g transform="matrix(.012,-0,0,-.012,9.1,11.762)"><path id="x4F" d="M381 665q131 0 226.5 -93t95.5 -239q0 -158 -96 -253t-238 -95q-137 0 -231 95t-94 238q0 142 92.5 244.5t244.5 102.5zM359 629q-89 0 -151 -74.5t-62 -208.5q0 -141 69 -233t175 -92q90 0 150.5 74t60.5 211q0 152 -69 237.5t-173 85.5z" /></g><g transform="matrix(.012,-0,0,-.012,17.893,11.762)"><path id="x48" d="M729 650v-28q-62 -5 -76 -19.5t-14 -75.5v-404q0 -62 13.5 -76t75.5 -19v-28h-268v28q65 5 79.5 19t14.5 76v199h-341v-199q0 -62 14 -76t76 -19v-28h-263v28q61 5 74.5 19t13.5 76v404q0 62 -14 76t-76 19v28h259v-28q-58 -5 -71 -19t-13 -76v-162h341v162&#xA;q0 61 -13.5 75.5t-72.5 19.5v28h261z" /></g></svg>) and the second (3<svg style="vertical-align:-3.25792pt;width:27.6875px;" id="M3" height="12" version="1.1" viewBox="0 0 27.6875 12" width="27.6875" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"><g transform="matrix(.017,-0,0,-.017,.062,7.675)"><use xlink:href="#x1D708" /></g><g transform="matrix(.012,-0,0,-.012,9.1,11.762)"><use xlink:href="#x4F" /></g><g transform="matrix(.012,-0,0,-.012,17.893,11.762)"><use xlink:href="#x48" /></g></svg>) overtones of the OH-stretching vibration mode. Two groups of OH-stretching vibration and FTIR absorption bands at 3390–3420 cm<sup>−1</sup> and 3560–3580 cm<sup>−1</sup> show reversible temperature-dependent shift. The low-frequency bands absent in pure synthetic hydroxylclinohumites are assigned to OH-planar defects caused by Ti-for-Mg substitution.

V. Hurai

M. Wierzbicka-Wieczorek

M. Pentr&#xe1;k

M. Huraiov&#xe1;

R. Thomas

A. Swierczewska

J. Lupt&#xe1;kov&#xe1;

X-Ray Diffraction and Vibrational Spectroscopic Characteristics of Hydroxylclinohumite from Ruby-Bearing Marbles (Luc Yen District, Vietnam)

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International Journal of Mineralogy