Chalk is the traditional blackboard alternative to writing on whiteboards. Non-toxic and dustless. Available in boxes of white or assorted colours.
Chalk is made from Calcium Carbonate which occurs naturally in Limestone. The Limestone is quarried, crushed, ground to fine particles then mixed with water to form a slurry. This is then formed into long thin rolls or sticks, baked slowly in an oven, cooled, cut to size and boxed.