rare calcite crystals in crystal cave from farcu mine

apuseni atracttion bauxite bihor calcite cave clear county crystal crystalline crystals equipment europe exploatation facets farcu gem gemstone geologic geological inclusions light limestone mine mineral mining museum natural polysilicate priceless purity quartz rare rock romania sightseeing silica silicates spectacular speleological stalactites stone structures tour tourist translucent transparent transylvania unique visitor white