Mine drainages of La Poderosa (El Campillo, Huelva, Spain), located in the Rio Tinto Basin (Iberian Pyrite Belt) generate carotenoid complexes mixed with copper sulfates presenting good natural models for the production of carotenoids from microorganisms. The environmental conditions of Rio Tinto Basin include important environmental stresses to force the microorganisms to accumulate carotenoid...

Several unusual forms of natural graphite from an alkaline pegmatite that crosscuts rischorrite in the Hackman Valley, Khibiny Massif, Kola Peninsula, Russia are described. The graphite occurs macroscopically in two forms: as spherical aggregates up to 2 cm in diameter of friable, radially-aligned fibers ~20 μm in cross section, and as finegrained surface coatings in cavities covering aegirine,...

It is recognized that magmatic activities have occurred along the Izmir Erzincan suture due to closure of Tethyan ocean. In western part Almus (Tokat), which situated around this zone, quartz veins fracture lines are observed in volcanics owing magmatism. There copper enrichments with an average thickness 70 cm volcanic rocks. Mineralization as vein type and epigenetic formation. Paragenesis co...

The Piquiri Syenite Massif, southernmost Brazil, is part of the post-collisional magmatism related to the Neoproterozoic Brasiliano-Pan-African Orogenic Cycle. The massif is about 12 km in diameter and is composed of syenites, granites, monzonitic rocks and lamprophyres. Diopside-phlogopite, diopside-biotite-augite-calcic-amphibole, are the main ferro-magnesian paragenesis in the syenitic rocks...

SUMMAaY. The Mineralogical Society celebrated its 5oth Anniversary in I926; this address attempts to summarize the substantial developments in the subject over the past 5o years and looks ahead to the future. Up to 1926, only the techniques of goniometry, optical investigation of non-opaques, and classical chemical analysis had been fully exploited. X-ray crystallography, though already I4 year...

Haynes, F.M., 1984. A geochemical model for sulfide paragenesis and zoning in the Cu-Fe--As--S system (Tsumeb, South West Africa/Namibia). Chem. Geol., 47: 183--190. The Cu-bearing hypogene mineralization at Tsumeb, South West Africa/Namibia, is interpreted to have resulted from the interaction of hot circulating Cu-rich saline solutions and host dQlomites. Fluids attending formation of the mai...