The world’s reliance on concrete, the second most consumed material after water, is leading to an environmental and resource crisis, with sand mining rates outstripping natural replenishment. Now, graphene derived from metallurgical coke, a coal-based product, could serve not only as a reinforcing additive in cement but also as a replacement for sand in concrete. When compared with concrete made using suitable sand aggregates, the concrete made using the graphene aggregate substitute was 25% lighter but just as tough.