English: Khurayyimite and associated minerals: a holotype specimen, contact of unaltered spurrite marble (brown) and altered spurrite marble (light), mainly composed of calcite, minerals of the ettringite-thaumasite series, Ca-hydrosilicates containing cavities with khurayyimite; b, c and d BSE images of typical spherulitic aggregates of khurayyimite: Cal—calcite, Fos—foshagite, Gnk—greenockite, HSi—mixture of Ca-hydrosilicates, Khu—khurayyimite and Spu—spurrite. The image is published in an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).