Inhomogeneous moldavites: the dependence of sculpture on chemical composition and glass flow structure

Abstract The sculpture of two moldavites was removed and their polished surfaces were etched in 2% HF. Moldavite A is structurally inhomogeneous. The deep grooves of natural sculpture had been formed in areas, in which the parallel flow of the fluidal structure (striae) was damaged. Moldavite B is not structurally inhomogeneous – no defects of the parallel flow of fluidal structure were found. However, moldavite B is chemically inhomogeneous. Based on the 38 EDX point analyses, two types of glass matter were found in sample B. The chemically less resistant glass α is poor in SiO 2 and K 2 O and rich in MgO, CaO and Na 2 O as compared with glass β. Thin layers of glass matters α and β occur successively in the area of moldavite B, where originally a deep groove existed. The rest of sample B is mostly composed of the β glass. Weathering indexes IPW, I KO and I W for glass α and β were counted. The direction and the type of the sculpture of moldavites under study depends clearly on the chemical composition and the structure of the glass material. There was no single-coloured analogue found to the two-coloured moldavites.