Haláp Hill is an eroded remnant of young (∼3 Ma) alkaline basalt in the western part of the Bakony–Balaton Highland Volcanic Field, Tapolca, Hungary. Cavities in the basalt contain miarolitic minerals (augite, apatite, magnetite, plagioclase and sanidine), zeolites (analcime, chabazite-Ca, chabazite-Na, garronite, gismondine, gmelinite-Ca, gmelinite-Na, gobbinsite, gonnardite-Na, natrolite, mesolite, phillipsite-Ca, phillipsite-K, phillipsite-Na and scolecite) and other secondary minerals (calcite, smectite-group minerals, goethite and Mn-oxides). Chabazite-Na, gmelinite-Ca, gonnardite-Na, phillipsite-Na and phillipsite-K are reported from Haláp Hill for the first time. The Ca-rich and Na-rich zeolites and abundant calcite were produced by hydrothermal alteration. Mineral assemblages were characterized by X-ray diffraction, differential thermal analysis, energy-dispersive spectrometry and wavelength-dispersive spectrometry. The secondary mineral assemblages were probably formed as a result of low-temperature hydrothermal activity at 50—100°C. Miarolitic minerals crystallized first in cavities in the basalt; they were followed by zeolite-group minerals and calcite. Analcime and phillipsite with or without chabazite/gmelinite/garronite or gobbinsite were the first zeolite-group minerals to crystallize; gonnardite-Na and natrolite crystallized later from Na-rich fluids. Calcite and smectite-group minerals crystallized continually. This paragenetic sequence is similar to others which have been reported in basalt from other localities in the Balaton Highland, Iceland and Northern Ireland.

An unusually diverse array of 25 secondary Te oxysalt minerals has been documented from Otto Mountain, California, and 18 of these from the Bird Nest drift sublocality. A paragenetic sequence for these minerals is proposed, using observed overgrowth relationships plus spatial association data and data from other localities. Apart from Te and O, the components Pb, Cu and H are essential in the majority of the minerals. The atomic Cu/Te ratio decreases through the paragenetic sequence. This, and the occurrence of minerals with additional components such as Cl–, CO32–, SO42– and Fe3+ at an intermediate stage, suggests nonmonotonic evolution of the parent fluids, reflecting differing access to or spatial distribution of various components. For the minerals with known crystal structures, two alternative 'structural units' were identified, one consisting only of the Te4+ or Te6+ oxyanion, while the other also included small, strongly-bound cations such as Cu2+. The degree of polymerization for the Te oxyanion correlated with the paragenetic sequence: the monomeric tellurate anions of early minerals were replaced progressively by dimers, chains and sheet structures, which may relate to a decreasing abundance of the 'network modifying' Cu2+ cation, analogous to Bowen's discontinuous reaction series in igneous rock-forming silicates. No relationship was seen between paragenetic order and the larger type of structural unit, or structural complexity as defined by information content. This contrasts with results in the literature for evaporite sulfates and pegmatite phosphates. While structure–paragenesis relationships may be widespread, the exact nature of such relationships may be different for different chemical systems and different paragenetic environments.

The zoned McMurry Meadows Pluton has been examined for REE and trace element variations in hornblende, sphene, apatite, allanite and zircon. Mineral separates (17), were analysed by INAA from four granitoids spanning the compositional range of the pluton (60%–75% SiO2). All of the phases examined exhibit significant compositional variations, with sphene having the largest changes in chondrite normalised REE patterns. Compositional variations in these minerals are related to paragenetic sequence and, as the whole rocks become more evolved, increases in partition coefficients; not subsolidus re-equilibration. Hornblende is only a dominant site for REE in granites where sphene is a later crystallising phase, otherwise allanite (LREE only) and sphene are the dominant whole rock sites for REE. Zircon and apatite normally contribute less than 10% each to the whole rock abundance of REE. Three zircon samples contain only small compositional differences and are interpreted as having crystallised from the bulk magma prior to differentiation. Zr variation in the pluton is nonlinear, first increasing and then decreasing with whole rock fractionation. A simple process, analogous to “restite unmixing” applied to the Zr variation, defines a bulk magma composition of about 63% SiO2, before differentiation of the zoned pluton. The modelled bulk magma need only have evolved by about 2·5% silica and still have produced the entire compositional range (60–75% SiO2) observed in the pluton.