material
Blackboard chalk
Pressed chalk or gypsum sticks for slate and chalkboard writing, usually white or pale. Not chalk as the mineral lemma alone, and not pastel-chalk as drawing pastel.
Also known as Chalkboard chalk · School blackboard chalk
material
Pressed chalk or gypsum sticks for slate and chalkboard writing, usually white or pale. Not chalk as the mineral lemma alone, and not pastel-chalk as drawing pastel.
Also known as Chalkboard chalk · School blackboard chalk