TOURCOMP: A program for estimating end-member proportions in tourmalines
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Abstract A Visual Basic program (TOURCOMP) has been written to recast the tourmaline composition into end-member components from electron microprobe data or more complete tourmaline analyses. TOURCOMP is a program based on a linear algebraic model that directly calculates the end-member proportions of tourmalines from their structural formulae. The program is developed for IBM-compatible personal computers running under the Windows™ operating system. The source code has been also translated and compiled in order to run on an Apple computer. Analytical problems, uncertainties concerning site occupancies, and the normalization procedure to determine the structural formula are the main error sources. However, the method of recalculating tourmaline end-members presented in this paper is considered to provide reasonably good results, bearing in mind the chemical complexity of tourmaline.Keywords:
Tourmaline
Normalization
IBM
Computer program
Microprobe
Tourmaline
Leucogranite
Nodule (geology)
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The Nedvědice orthogneiss is characterized by high contents of F, and B2O3, manifested by the presence of F-rich muscovite, F-rich tourmaline, and rare fluorite-tourmaline layers. Tourmaline forms subhedral grains in the orthogneiss, prismatic crystals in muscovite and fluorite-tourmaline layers in the orthogneiss. Tourmaline is also present as fine-grained layers in the muscovite layers. In our study, two types of tourmaline zoning were distinguished in the four types of studied rocks. Our results show a significant change of tourmaline composition during metamorphic recrystallization.
Tourmaline
Muscovite
Recrystallization (geology)
Massif
Pegmatite
Fluorite
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Abstract Three distinct paragenetic and compositional types of tourmaline were described from the Velence Granite and the surrounding contact slate. Rare, pitch-black, disseminated tourmaline I (intragranitic tourmaline) occurs in granite, pegmatite, and aplite; very rare, black to greenish-gray, euhedral tourmaline II (miarolitic tourmaline) occurs in miarolitic cavities of the pegmatites; abundant, black to gray, brown to yellow or even colorless, acicular tourmaline III (metasomatic tourmaline) occurs in the contact slate and its quartz-tourmaline veins. Tourmaline from a variety of environments exhibits considerable variation in composition, which is controlled by the nature of the host rock and the formation processes. However, in similar geologic situations, the composition of tourmaline can be rather uniform, even between relatively distant localities. Tourmaline I is represented by an Al-deficient, Fe 3+ -bearing schorl, which crystallized in a closed melt-aqueous fluid system. Tourmaline II is a schorl-elbaite mixed crystal, which precipitated from Li- and F-enriched solutions in the cavities of pegmatites. Tourmaline III shows an oscillatory zoning; its composition corresponds to schorl, dravite, and foitite species. It formed from metasomatizing fluids derived from the granite. This is the most abundant tourmaline type, which can be found in the contact slate around the granite.
Tourmaline
Pegmatite
Metasomatism
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Tourmaline is a kind of silicate mineral which contains boron as a main element and several other minor elements such as lithium,sodium,iron,magnesium,aluminum,these elements build up the ring structure of silicate minerals.Tourmaline is consisted of lithium tourmaline,black tourmaline and magnesium tourmaline.Taking the black tourmaline as an example,the crystal structure was introduced in this paper and the technologies for preparation of micro-tourmaline and nano-tourmaline powder materials were summarized in this article.
Tourmaline
Silicate minerals
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By using the infrared reflection spectrum analysis technique, natural tourmaline and imitation tourmaline, similar tourmalines were investigated. The results show that the main absorption peaks of natural tourmaline are seven peaks at 1314cm-1, 1118cm-1, 1039cm-1, 999cm-1, 601cm-1, 513cm-1, 454 cm-1. The main absorption peaks of composite tourmaline and imitation tourmaline are different from natural tourmaline. The results are useful for identifying them.
Tourmaline
Reflection
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Foitite tourmaline was heated at 400-1000 ℃ for 2 h.Effect of heat treatment on tourmaline powder phase structure,surface structure of the foitite tourmaline was studied by means of X-ray diffraction,Fourier transform infrared absorption spectroscopy and laser Raman spectroscopy.The results show that tourmaline cell volume decreases with increasing the heat treatment temperature,and has a minimum value at 700 ℃.The heat treatment temperature has great influence on the surface electrical properties of tourmaline,when the temperature reaches 500 ℃,Zeta potential value is up to-48 mV.After heat treatment,the phase of tourmaline has been changed from Foitite tourmaline into Bouguer tourmaline,when the temperature is higher than 900 ℃,tourmaline decomposes to form Fe2O3 and Al4B2O9.Heat treatment can not only oxide Fe2+ to Fe3+,but also change the site of ions in the structure of tourmaline(Y,Z position).
Tourmaline
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