Emeralds from Colombia are among the most highly-prized and valuable gemstones. Their growth phenomena including information about the geology of the area were described in detail by Pig-natelli et al. (2015, 2022) and Schmetzer and Martayan (2023). Here, we present data obtained by scanning electron microscopy (SEM), electron microprobe analysis (EMPA), and infrared absorption spectroscopy (IR) for five emerald crystals. The surface of the crystals shows both, growth phe-nomena as well as dissolution phenomena, the latter as etch pits (EP). Such EP have been used previously for other beryl types, mainly from pegmatitic environments (Kurumathoor and Franz, 2018); the Colombian emeralds come from low-grade metamorphosed black shales and thus offer the possibility to extend the use of EP as a provenance indicator to other types of beryl deposits. Internal structures are manifested in chemical zoning, investigated by EMPA and micro-X-ray fluo-rescence (µXRF). The crystals are characterized chemically by EMPA, polarized IR spectroscopy of oriented crystals showed the presence of fluids in the channels of the beryl structure.
The soil state factors climate and time are of growing interest in respect to landscape and consequently soil evolution. Climate change can have significant impact on the global biogeochemical cycle by altering the type and rate of soil processes and the resulting soil properties. Direct and dramatic ecological responses to this impending warming are expected. Climatic warming is thought to increase soil temperature and to change many critical factors in plant productivity, phenology and succession. A main unknown parametre is the reactivity of soils and the rate of reactions. - Consequently, a soil sequence along an elevational gradient ranging from subtropical to subalpine climate zones in the Etna region (Sicily, southern Italy) are investigated in respect of organic C, kaolinite and crystalline to non-crystalline Al- and Fe-phases. Special emphasis is given to the stabilization of soil organic carbon (SOC) and its interaction with the inorganic phases. Furthermore, a weathering sequence with soils developing on volcanic, trachy-basaltic parent materials with ages ranging from 100 - 115000 years in the Etna region serve as the basis to analyse and calculate the accumulation and stabilisation mechanisms of soil organic matter (SOM), the transformation of pedogenic Fe and Al, the formation and transformation of clay minerals, the weathering indices and, by means of mass-balance calculations, net losses of the main elements.