This study focused on the formation of the jarosite-alunite solid solution at relatively low temperature, 90 ◦C. It was found that the transition from jarosite to alunite results in significant changes in the powder X-ray diffraction pattern, the infrared spectrum and thermal behavior when the degree of substitution reached ≥50%. The initial Al/(Al + Fe) in solution, however, required to achiev...

Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) covers a wide spectral region with 14 bands from visible to the thermal infrared. The different band ranges can be capable of discriminating and mapping surface rocks and predicting pathfinder minerals (i.e. alunite, kaolinite etc.) on alteration assemblages of potential targets. The aim of this study is to compare two diffe...

The thermal decomposition of alunite and of mixtures of alunite with dickite or quartz or both has been studied, and X-ray determinations of the products at various stages of the decomposition have been made. Between 6oo and 7oo ~ the product from alunite is a mixture of anhydrous alum and amorphous alumina; between 7oo and 770 ~ the anhydrous alum breaks down into aluminium sulphate and alkali...

Synthetic, polycrystalline samples of alunite [K0.88(H3O)0.12Al2.64(SO4)2(OH)4.92(H2O)1.08] and oxonium-substituted alunite [H3OAl2.87(SO4)2(OH)5.61(H2O)0.39] have been investigated using incoherent, inelastic neutron-scattering (IINS) methods in order to determine the nature of the non-OH “H2O”. IINS measurements were made on non-deuterated samples at 20 K using the HRMECS chopper spectrometer...

The alunite supergroup consists of more than 50 representative minerals with the general formula A B 3 (XO 4) 2 (OH) 6 , where A may be occupied by Na, is the trivalent cation , Al 3+ or Fe 3+ , but also Cu 2+ or Zn 2+ and X is the tetrahedral anion, S, P or As [1, 2]. The minerals of this supergroup form numerous complex solid solutions which crystallize in a rhombohedral system, space group R...

A field-mapping and crystal-chemical study of two aluniteand halloysite-rich deposits in the Turplu area, situated northwest of Balıkesir on the Biga Peninsula of northwest Turkey reveals a mineralogically diverse and a potentially economic clay deposit. The mineral assemblage along fault zones is dominated by halloysite and sometimes alunite. The alunite is nearly end-member in composition (a ...

Big Rock Candy Mountain is a prominent center of variegated altered volcanic rocks in west-central Utah. It consists of the eroded remnants of a hypogene alunite deposit that, at ~21 Ma, replaced intermediate-composition lava flows. The alunite formed in steam-heated conditions above the upwelling limb of a convection cell that was one of at least six spaced at 3to 4km intervals around the marg...

Minamiite has been discredited and renamed natroalunite-2c to show a double unit-cell structure and natroalunite can be designated as natroalunite-1c to show a single unit-cell structure. Kintoreite can be designated as kintoreite-1c to show the same single unit-cell structure, and IMA 1993-039 is a new superstructure of kintoreite and can be designated as kintoreite-2c to show a double unit-ce...