A large number of polished stone implements from Palaeolithic to Bronze Age sites of Northern Italy and Southern France are made of high-pressure (HP) metamorphic rocks (eclogite and related rocks), mainly consisting of Na-pyroxene (jadeite to omphacite) from the metamorphic belt of the Western Alps. The standard archaeometric study of prehistoric stone implements follows a procedure that is in...

We investigate the relationship between the petrology and visible–near infrared spectra of the unbrecciated eucrites and synthetic pyroxene–plagioclase mixtures to determine how spectra obtained by the Dawn mission could distinguish between several models that have been suggested for the petrogenesis of Vesta’s crust (e.g., partial melting and magma ocean). Here, we study the spectra of petrolo...

Introduction – Lunar meteorite Northwest Africa (NWA) 032 is an unbrecciated mare basalt, discovered in 1999, whose modal mineralogy is characterized by phenocrystic olivine, pyroxene and chromite, with a groundmass containing feldspar, pyroxene, ilmenite, troilite and other trace metals [1]. Shock melt occurs in veins throughout the sample as well. Fagan et al. [1] observed that the major elem...

The title compound, dicalcium nonaoxidodistannate(IV)dialuminate, is the second example which crystallizes in the isotypic structure of a pyroxene silicate, Na(2)Ti(2)Si(2)O(9) (ramsayite). (∞) (1)[Sn(2)O(8)] chains and pyroxene-type (∞) (1)[Al(2)O(6)] chains are formed along the b axis by sharing O atoms. The Ca atoms are situated in the resulting channels and exhibit a coordination number of 7.

Acid weathering of plagioclase–pyroxene mixtures has been investigated with an open system kinetic dissolution model. The modeling reveals that elevated plagioclase/pyroxene ratios observed in some low-albedo martian regions and atmospheric dust could be partially caused by preferential dissolution of pyroxenes at pHs below ∼3–4. Surface materials with smaller grain sizes, affected by lower pH ...