Quartz is omnipresent on earth. The waters circulating deep inside the continental crust cracks undergo high temperatures and high pressure, and their pH is fairly high. These waters can dissolve a high amount of silica in the depths of the crust. If the water rises, the temperature and the pressure decrease : the silica then crystallizes on the edges of the crack and form beautiful translucent faceted crystals, as one can see in the Alps. Nevertheless, the great quartz' family covers an extended variety of stones with a wide color range, depending on which minerals got trapped into the crystal lattice.