Wonderful crystalline formation of green melanterite with chalcanthite (100% natural) from this famous mine in Tuscany. In this particular specimen, of stalactitic origin, the two minerals are mixed, giving rise to colours that shade from green to blue to light blue, with a greener nucleus due to the greater presence of melanterite. A specimen of good size, with good aesthetic value , certainly sought after by collectors for its unique formation and rarity. The first two images were taken in backlight. Specimen supplied with plastic box with cover , because the mineral is sensitive to dehydration. It should be kept closed for optimal preservation. Even better if you place a cotton ball soaked in water inside the closed box , to increase humidity inside. Specimen photographed under bright light.