Coupons were dried and analyzed without removing scale from the surface. We used a Rigaku Ultima IV X-ray diffractometer with a copper K𝛼 radiation source, operated at 35 kV and 30 mA. Scans were acquired over the range 10-70° (2𝜃) with a step size of 0.04° and a scan speed of 0.8° min -1 . The powder diffraction file numbers corresponding to standards referenced in the manuscript are listed in Table .