# How to recrystallize boric acid into flakes?

I am putting 100 g of boric acid, 400 g of water and trying to crystallize at low temperature and letting cool slowly, however it recrystallizes as needle like texture. I need soft large crystals like mica. Can someone help out?

The ratio seems about right, though the solution could be a bit more saturated as the solubility of boric acid in $\pu{100 mL}$ of boiling water is $\pu{27.5 g}$, so for $\pu{400 mL}$ of water you can theoretically use $\pu{110 g}$ of boric acid.
P. S. When drying the crystals at the end after rinsing them with cold water on a filter make sure not to exceed $\pu{130 °C}$, otherwise boric acid will start to decompose and form metaboric acid $\ce{HBO2}$, then subsequently upon further heating, $\ce{H2B4O7}$, and, finally, $\ce{B2O3}$ [1, pp. 119–120].