Coinage metal-thiolate assemblies exemplify hierarchical structure and structure-property relationships. They comprise structurally weak hydrogels of stacked sheets. Inclusion of an anti-solvent in synthesis of these materials fundamentally changes their structure, resulting instead in colloidal amorphous metal complexes. The colloids undergo a hydration-dependent and reversible sol-gel transition. Because the colloids are flexible, they morph in the sol-gel transition to eliminate void spaces, producing a surprisingly rigid gel. Sodium ions that are aqueous in the sol transition to bridge colloids in the gel, rigidifying the system. The underlying structure results in a material that is strikingly disparate from compositionally similar materials. The distinct rheological properties that emerge that may render coinage metal-thiolate assemblies as engineering-grade materials.