Effect of chemically induced fracturing on the ice nucleation activity of alkali feldspar

Abstract. Feldspar is an important constituent of airborne mineral dust. Some alkali feldspars exhibit particularly high ice nucleation (IN) activity. This has been related to structural similarities the (101?0) prism planes and (100) feldspar. Here effect generating feldspar surfaces with close orientation by means chemically induced fracturing on IN activity was investigated experimentally. To this end, gem-quality K-rich shifted towards more Na-rich compositions cation exchange NaCl–KCl salt melt at 850 ?C. By procedure, a system parallel cracks plane induced. Droplet-freezing assay experiments performed grain mounts cation-exchanged revealed increase in overall density ice-nucleating active site (INAS) respect untreated In addition, annealing 550 ?C subsequent primary further enhanced INAS led exceptionally temperatures. Although very efficient experiment, halide unlikely be relevance conditioning nature. However, parting similar as may generated lamellar microstructures resulting from exsolution initially homogeneous feldspar, widespread phenomenon natural known perthite formation. Perthitic indeed show highest We tentatively ascribe preferential exposure crystal oriented sub-parallel (100).