Schorl is a member of the Tourmaline family and a member of the silicate group of minerals.
All Tourmalines contain iron but Schorl contains more than any other form of the mineral and it is the iron content that gives it its black colour. This is why the mineral is often referred as Black Tourmaline.
Black Tourmaline opaque prismatic crystals can be several metres in length. The mineral resembles all the other forms of Tourmaline in almost every detail, apart from its colour - black.
All members of the Tourmaline family are complex silicates that contain boron. Their different colours are determined by the amount of aluminium, iron, lithium, magnesium, manganese or sodium they contain.
Black Tourmaline is heavy and quite hard at 7.0 to 7.5 on the Mohs hardness scale.