Mineral assemblages of primary and secondary Be-minerals were examined in intraplutonic euxenite-type NYF pegmatites of the Třebíč Pluton, Moldanubian Zone occurring between Třebíč and Vladislav south of the Třebíč fault. Primary magmatic Be-minerals crystallized mainly in massive pegmatite (paragenetic type I) including common beryl I, helvite-danalite I, and a rare phenakite I. Rare primary hydrothermal beryl II and phenakite II occur in miarolitic pockets (paragenetic type II). Secondary hydrothermal Be-minerals replaced primary precursors or filled fractures and secondary cavities, or they are associated with ,,adularia" and quartz (paragenetic type III). They include minerals of bohseite-bavenite series, less abundant beryl III, bazzite III, helvite-danalite III, milarite-agakhanovite-(Y) III, phenakite III, and datolite-hingganite-(Y) III. Chemical composition of the individual minerals is characterized by elevated contents of Na, Cs, Mg, Fe, Sc in beryl I and II; Na, Ca, Mg, Fe, Al in bazzite III; REE in milarite-agakhanovite-(Y) III; variations in Fe/Mn in helvite-danalite and high variation of Al in bohseite-bavenite series. Replacement reactions of primary Be-minerals are commonly complex and the sequence of crystallization of secondary Be-minerals is not defined; minerals of bohseite-bavenite series are mostly the latest. Beryl usually occurs in pegmatites with rare tourmaline, whereas helvite-danalite bearing pegmatites are tourmaline-rich. Abundant tourmaline in pegmatites with helvite-danalite and its scarcity in beryl-bearing pegmatites indicate that early tourmaline crystallization affected activity of Al in the parental medium and thus may have controlled formation of primary Be-minerals (beryl-higher Al, helvite-danalite-lower Al) which crystallized later. Secondary Be-minerals with dominant minerals of bohseite-bavenite series and milarite suggest high activity of Ca in fluids. Variations in chemical composition (Al contents) of bohseite-bavenite series were controlled by the chemical composition of the precursor. High variability of primary magmatic Be-minerals within a single pegmatite district is exceptional and it is constrained by variable activities of Si and mainly Al, divalent cations-Ca, Mn, Fe, Zn and Mg, trivalent cations-REEs, Sc, and B, S, and f O2 in the individual pegmatites.

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Mineral assemblages and chemical composition of bavenite-bohseite were examined at 15 granitic pegmatites from the Bohemian Massif, Czech Republic. Three types distinct in their relation to primary Be-precursors, mineral assemblages, morphology, and origin were recognised. (i) Primary hydrothermal bavenite-bohseite crystallised in miarolitic pockets from residual pegmatite fluids. Secondary bavenite-bohseite occurs in two distinct types: (ii) a proximal type spatially restricted to pseudomorphs after a primary Be-mineral (beryl > phenakite, helvine-danalite), and (iii) a distal type on brittle fractures and fissures of host pegmatite. Their mineral assemblages are highly variable: (i) axinite-(Mn), smectite, calcite, pyrite, (ii) bertrandite, milarite, secondary beryl, bazzite, K-feldspar, muscovite-illite, scolecite, gismondine-(Ca), analcime, chlorite, and (iii) muscovite, albite, quartz, epidote, pumpellyite-(Mg), pumpellyite-(Fe 3+ ), titanite, chlorite. The electron probe micro-analyses showed in addition to major constituents (Si, Ca, Al) also minor concentrations (in apfu) of Na (≤0.24), Fe (≤0.10), Mn (≤0.10), and F (≤0.36). The (i) hydrothermal miarolitic bavenite-bohseite is mostly Al-rich (2.00-0.67 apfu) relative to (ii) proximal bavenite-bohseite and bohseite after beryl, phenakite and helvine-danalite (1.56-0.46, 0.70-0.05, 1.02-0.35 apfu, respectively) and

The Mach Effect Thruster (MET) is a propellant-less space drive which uses Mach's principle to produce thrust in an accelerating material which is undergoing mass-energy fluctuations, [1]-[3]. Mach's principle is a statement that the inertia of a body is the result of the gravitational interaction of the body with the rest of the mass-energy in the universe. The MET device uses electric power of 100-200 Watts to operate. The thrust produced by these devices, at the present time, are small on the order of a few micro-Newtons. We give a physical description of the MET device and apparatus for measuring thrusts. Next we explain the basic theory behind the device which involves gravitation and advanced waves to incorporate instantaneous action at a distance. The advanced wave concept is a means to conserve momentum of the system with the universe. There is no momentun violation in this theory. We briefly review absorber theory by summarizing Dirac, Wheeler-Feynman and Hoyle-Narlikar (HN). We show how Woodward's mass fluctuation formula can be derived from first principles using the HN-theory which is a fully Machian version of Einstein's relativity. HN-theory reduces to Einstein's field equations in the limit of smooth fluid distribution of matter and a simple coordinate transformation.