Occurs associated with alunogen, pickeringite, epsomite, melanterite, gypsum and native sulfur. The European Space Agency's Mars Express found evidence of perhaps epsomite and kieserite. It occurs associated with pyrite, marcasite, halotrichite, pickeringite, epsomite, potash alum, melanterite and gypsum. It occurs in association with basaluminite, gibbsite, epsomite, gypsum, celestine, dolomite and goethite. It occurs with kalinite, alunogen, epsomite, melanterite, copiapite and gypsum. Associated minerals include gypsum, halite, thenardite, trona, glauberite, and epsomite. Rare formations called helictites, plus gypsum, epsomite and prehistoric flint quarries add variety. Goslarite's cleavage is perfect in {010}, as for epsomite and morenosite. Associated minerals include pisanite, chalcanthite, epsomite, pickeringite, halotrichite and other sulfate minerals. Goslarite belongs to the epsomite group which also includes epsomite (MgSO) and morenosite (NiSO). The European Space Agency's Mars Express found possible evidence of the sulfates epsomite and kieserite. In summer it deposits epsomite ("Epsom salts"). Associated minerals include melanterite, epsomite, jarosite, gypsum, sulfur, pyrite, marcasite and limonite. The heptahydrate (epsomite) readily loses one equivalent of water to form the hexahydrate. Epsomite is the natural analogue of "Epsom salt".