From the attached press release: "New, colorful, all-clay construction block developed at Armour Research Foundation of Illinois Institute of... Show moreFrom the attached press release: "New, colorful, all-clay construction block developed at Armour Research Foundation of Illinois Institute of Technology, Chicago, weighs less than conventional concrete blocks. Al Litvin, supervisor of masonry materials, holds the ceramic block after removing it from molding machine." Photographer unknown. Date of photograph unknown. Date listed is approximate. Show less