Ключевые слова: america, arizona, below ground, calcite, cave, cave system, cavern, caverns, caves, crystal, crystalline, crystalline structure, crystals, dark, flash photography, formation, geological, geology, grand canyon caverns, granite, historic, illuminated, illumination, landmark, light, limestone, mineral, minerals, natural, natural formation, natural landmark, nature, north america, onyx, peach springs az, quartz, recreation, rock, rugged, selenite, shadow, southwest, stone, structure, textured, textured surface, tourism, travel, underground, usa,