Comparison of geological, mineralogycal, gemologycal and technologycal properties of oltu stone and russia stone (Georgian stone)

Within the scope of this study, the geologic, mineralogic, gemological and technological properties of Oltu stone (NE of Erzurum) and Russian (Georgian) stone have been determined and compared with the help of compherensive research studies carried out in two different countries and geography. They are both in same class of black amber. Their general color is black and soft when fresh but hardens in atmospheric conditions. Oltu stone, which is being extracted from the villages of Oltu county in the northeast part of Erzurum, in order to be used in small workshops for stone processing with simple techniques, is generally black in color, having brown streak color, 3 of hardness, relatively heavy, concoidal in diffaraction pattern, tough and everlasting ornamental stone and occur as discontinuous and irregular lenses in our country. Russian (Georgian) stone, which is being extracted from the villages in the northern and northeastern part of K?ut?aisi? county of Middle Georgia, in order to be used in stonework in advanced large workshops for stone processing with modern techniques, is generally black in color, having black streak color, 2,5 of hardness, relatively light and occur as regular bands of various thicknesses. According to the studies; both gemstones occur in the same geological environment and time, have the same mineralogical structure but differ from each other from the point of difference in plantal material and grade of regional methamorphism. Although both have very similar mineralogical properties, Oltu stone is much more superior to Russian (Georgian) stone from the point of gemological features. It is defined that, although Oltu stone and Oltu is far front with high quality of technological infrastructures being used in producing ornamental stone, since it is ten times more expensive than Russian (Georgian) stone, resulting a gap in price, Russian (Georgian) stone can easily enter, legally or illegally, to our country and causes a negative image on Oltu stone, Oltu province and negative effect on economy. Key words: Oltu Stone, Russia Stone, (Georgia Stone), Gemology