Mineralogical, textural and chemical analyses of clay-rich materials following firing, evidence that initial mineralogical differences between two raw materials (one with carbonates and the other without) influence the textural and mineralogical evolution of the ceramics as T increases from 700 to 1100°C. Mineralogical and textural changes are interpreted considering local marked disequilibria ...

This study aimed at demonstrating complementary roles offered by both Fourier transform infrared (FTIR) spectrophotometry and x-ray powder diffraction (XRPD) techniques in characterizing clay size fraction of kaolins. The clay size fraction of kaolin samples obtained from Kgwakgwe, Makoro, Lobatse and Serule kaolin occurrences and deposits in Botswana were characterized using laser diffraction ...

Introduction: Sahara 99201 (provisional name) is a new ureilite weighing 91g collected from the Sahara desert during 1999. The sample has been analysed to determine both mineralogy and petrography and also its light element stable isotopic composition. Methodology: Mineralogical analyses were carried out using a Cameca SX100 electron microprobe, with a beam current of 20nA, accelerating voltage...

In recent years, the gemstone market has been flooded with stones of questionable origin. Frequently, even thorough analysis by a qualified jeweler cannot reveal unequivocally whether the gemstone is genuine or fake. In the worst case, sophisticated analytical methods struggle to differentiate modified diamonds, causing considerable concern to the international gemstone trade. Raman microspectr...

Myocarditis has long been recognized as a complication of rheumatic fever, diphtheria, scarlet fever and whooping cough. It also occurs in association with poliomyelitis and more rarely with other virus infections such as influenza, mumps, psittacosis, infectious mononucleosis, primary atypical pneumonia, varicella, measles, infectious hepatitis and yellow fever (Lyon, 1956; Silber, 1958). Myoc...

Introduction: Light stable isotopes provide insights and constraints on nebular and parent body processes. Lithium isotope studies of chondrites offer such potential, with some specifically unique aspects. Lithium is monovalent, the lightest of nongaseous elements, it has a 15% mass difference between its 2 isotopes (Li and Li), it is fluid mobile, and it is one of the fastest diffusing element...

Introduction: Key issues regarding the early evolution of planetesimals include the timescales of accretion, core formation, and magmatism. The short-lived Hf-W system has proven particularly useful as a chronometer for these early planetary processes. For instance, W model ages for magmatic iron meteorites reveal that core formation in their parent bodies occurred within ~1 Myr after formation...

Introduction: Yamato 980459 (Y98) is an olivine-phyric basaltic shergottite [1] composed of 48% pyroxene, 26% olivine, 25% mesostasis, and 1% other minerals. Unlike the other Martian basalts, it contains no plagioclase. Olivine in Y98 is the most magnesian of all Martian meteorites. Thus Y98 is believed to be the most primitive [2] and its composition may be the closest to a primary or direct m...

Introduction: Previous studies of the Re-Os systematics of chondrites have documented considerable variation in the Re/Os ratios of whole rock samples [1,2]. For some whole rock chondrites, Re-Os systematics display large deviations from the primitive isochron that are considerably larger than deviations in other isotope systems [1]. Possible interpretation of these facts is that the Re-Os syst...

Introduction: Some terrestrial high-Ca pyroxenes (clinopyroxenes) produce anomalous near-infrared (NIR) reflectance spectra, “Type B” patterns, with absorption at about 2 um [1, 2]. This absorption band seems to indicate that Fe ion is in the silicate crystal’s larger, M2 octahedral site; Fe cannot actually be there, however, because Ca fills that site [3]! Pyroxenes are the principle phases de...