Although sintering of NaCl at room temperature has also been reported11,12, this salt is prone to densification at such mild conditions due to its very high solubility in water (360g/l). Instead, we present for the first time the accelerated sintering in water at 25℃ of an inorganic compound that is only moderately soluble in water (1.9g/l; ref. 13). This pushes further down the lower sintering temperature limit and eliminates the need for hydrothermal conditions to accomplish sintering of sparsely soluble compounds in water.