Mineralogy and structure of selected raw materials as reason of their quality

Paper present results of mineralogical examination of various genetic types of flints and obsidian were performed using polarizing light microscopy, SEM and EDX methods were performed during last 3o years. Various method were used for determining possible relations between internal structures of these raw materials and relations to the best directions for processing. Analyses showed that the best directions for preparation of flint implements are parallel to directions of optical orientation of micro crystalline quartz present in flint. This orientation was the result of the recrystallization process of silica from opal to chalcedony and quartz. The type of processes known as ageing of silica active and observed in flint nodules have persisted for a million years. The growth of microcrystals in primary opal of flints goes a specially well perpendicularly to the direction of stress, i.e., perpendicular to the thickening of rock layers (mostly limestones). Performed investigation confirmed the primary flint nodules formed in situ from sponga organisms show regular nodule shapes. Secondary flints formed due to migration of dissolved silica in deposited sediment had mostly irregular shape. Secondary crystals of quartz present in these flints do not show space orientation and because of this the secondary flints are bad for knappin