Obelisk

Chalk is a humble material with a remarkable past. Though today chalk is associated with scratching out equations on a blackboard, this remarkable medium is a type of limestone, created from the crushed shells of billions of phytoplankton called Coccoliths, whose corpses built up over millions of years into stone strata that now underlays much of Europe. Chalk has been used as a mark-making tool since the earliest homosapiens, with early chalkwork appearing in Paleolithic cave drawings. read more