Bicolor tourmaline specimens are among the most striking and highly coveted items in the mineral collecting world. These unique gemstones belong to the elbaite species of the tourmaline group. They feature two distinct, vivid colors within a single, naturally terminated crystal. This dramatic color zoning occurs when the concentration or composition of trace elements (like iron, manganese, or lithium) changes in the surrounding fluid environment while the crystal is actively growing… Color Zoning Patterns: Crystals can be zoned horizontally across their length—such as transitioning from a rich pink or deep blue base to a vibrant green cap. They can also grow concentricly parallel to their length… Watermelon Tourmaline: The most famous concentric variety. It features a pink core surrounded by a green outer skin, mimicking the appearance of a watermelon slice…. From Afghanistan Weight : 101 grams Size : 50x42x42mm