Tourmaline is a complex boron silicate mineral that comes in a wide variety of colors, making it one of the most versatile gemstones. It can be found in single colors, bi-color, or even tri-color combinations. The most common colors include pink, green, blue, yellow, and black, with each color representing different varieties of tourmaline.

Tourmaline is known for its unique crystal structure, which can create stunning visual effects, such as pleochroism, where the color appears to change when viewed from different angles. It has a hardness of 7 to 7.5 on the Mohs scale, making it durable enough for everyday jewelry.

Metaphysically, tourmaline is believed to have protective properties, promoting grounding and balance, and is often used in crystal healing practices. If you have more specific questions about tourmaline or its varieties, feel free to ask!