Well formed, big, cubic, gem and lustrous penetration twins of fluorite crystals on matrix from world famous locality - Rogerly Mine. Lustrous fluorite cubes are well coloured - dark emerald green in colour with a strong blue daylight fluorescence, and an even stronger purple-white fluorescence under long wave UV light. This amazing fluorite crystals change colour in different lights - in natural light they are blue, in artificial light they are green. Main crystal size - 1.8 cm. Minor demages. Specimen mounted to acrylic base.