What is Tourmaline? Tourmaline is a mineral group known for its wide variety of colors. Among these, bi-color tourmaline is one of the most popular and highly demanded varieties. Its rarity makes it more expensive compared to most other tourmaline colors, second only to the coveted Paraiba tourmaline. Bi-color tourmaline is also commonly referred to as "watermelon tourmaline" due to its distinctive and striking appearance.Tourmaline is a complex borosilicate mineral that contains a combination of elements such as aluminum, iron, magnesium, lithium, or potassium. Its chemical composition can vary widely, resulting in an extraordinary range of colors. Tourmaline crystallizes in the trigonal system and typically forms in elongated, prismatic crystals with vertical striations. It has a hardness of 7–7.5 on the Mohs scale, making it a durable gemstone.Associations and PropertiesGeological AssociationsTourmaline is commonly found in granite pegmatites, metamorphic rocks, and hydrothermal veins.It is often associated with quartz, feldspar, lepidolite, and beryl in pegmatite deposits.Notable sources include Brazil, Madagascar, Afghanistan, and Nigeria.Cultural and Mystical AssociationsTourmaline is believed to possess protective and grounding properties.Watermelon tourmaline (bi-color variety) is often associated with emotional healing and balance.It is a popular stone in crystal healing practices for promoting creativity and harmony.Optical PropertiesTourmaline exhibits pleochroism, where it displays different colors when viewed from different angles.Some specimens show chatoyancy (cat's-eye effect) or even asterism (star effect) when cut and polished properly.