Statement 1 : Crystals of hydrated calcium sulphate gypsum : $\left({\mathrm{CaSO}}_4.2{\mathrm{H}}_2\mathrm{O}\right)$ are soft and easily cleaved.

Statement 2 : Crystals of anhydrous calcium sulphate (anhydride : ${\mathrm{CaSO}}_4$) are very hard and very difficult to cleave.

Within the ${\mathrm{Ca}}^{2+}/{\mathrm{SO}}_4^{2-}$ layers, the ions are held together by strong electrovalent bonds. But these separated ${\mathrm{Ca}}^{2+}/{\mathrm{SO}}_4^{2-}$ layers are linked by relative weak H - bond. The weakest H - bonds link ${\mathrm{SO}}_4^{2-}$ ions in the intermediate region. Consequently, the gypsum can be readily cleaved and stretched along the layer of water molecules.

Anhydride has a completely ionic structure involving only ${\mathrm{Ca}}^{2+} \mathrm{and} {\mathrm{SO}}_4^{2-} \mathrm{ions}.$