Chalk formation occurs primarily in marine environments where tiny marine organisms, such as coccolithophores, thrive. These organisms produce calcium carbonate plates, which accumulate on the ocean floor after they die. Over millions of years, layers of these sediments compact and lithify, transforming into chalk rock. Chalk is typically white or light-colored and is found in large deposits, particularly in regions like the White Cliffs of Dover in England. The soft, porous nature of chalk makes it useful for various applications, including writing, construction, and as a soil conditioner in agriculture.