The best varieties are black and pitchy in lustre, or even bright and scarcely to be distinguished from true coals.
Bright, glance or pitch coal is another brilliant variety, brittle, and breaking into regular fragments of a black colour and pitchy lustre.
C. Ullmann's name of stilpnosiderite, from the Greek ariAirvOs (shining) is sometimes applied to such kinds of limonite as have a pitchy lustre.
Rosin varies in colour, according to the age of the tree whence the turpentine is drawn and the amount of heat applied in distillation, from an opaque almost pitchy black substance through grades of brown and yellow to an almost perfectly transparent colourless glassy mass.