Soft coal is a type of coal that is relatively low in carbon and ash content. CANNEL coal, also known as candle coal, is a type of soft coal that is characterized by its bright luster and ability to burn with a long, yellow flame. LIGNITE is another type of soft coal that is brownish-black in color and has a high moisture content. Bituminous coal is the most abundant type of soft coal and is characterized by its black color and glossy sheen.