What does it look like?
What is it?
Ettringite is a mineral that is produced as portland cement dries out. It is a calcium, aluminum hydrated sulfate silicate, so is a pretty complicated structure inorganic structure that varies in composition depending on the environment. Though ettringite is present in fresh concrete, it is thought that as the cement ages more ettringite can form and cause damage to the structures from within. There’s lots of research looking into stopping this.
Where did the structure come from?
This particular structure of ettringite that we have featured was presented in the journal Nature in 1968, and the atomic parameters for this can be found on the American Mineral Database.