brown. One of the Human Hair Wigs fascinating phenomena of brown tourmaline gemstones is their pleochroism; the ability to exhibit different colors depending on the viewing angle. This results in interesting multicolor tourmaline Hair Extensions gemstones that may be brown, yellow and green all in one stone. Brown tourmaline has a Mohs hardness of 7-7.5 and a vitreous luster. Trade Brazilian hair names for brown.