An injectable bone mineral substitute material composition with the capability of being hardened in a body fluid in vivo, which comprises at least one calcium phosphate component and at least one calcium sulfate component as a dry mixture mixed with an aqueous liquid, and at least one accelerator, the at least one calcium sulfate component being particulate hardened calcium sulfate, which has a specified particle size that is in order to confer injectablity to the composition. The invention also concerns the bone mineral substitute material produced from the composition as well as methods and uses thereof.