disclosed are compositions derived of mixtures of choline ion salts in aqueous solution with suspended particulates of sparingly soluble borate minerals or with alkali or alkaline earth borate salts , boric acid and its ester derivatives and salts , or other aqueous soluble borate forms . these compositions are useful as cross - linkers for polysaccharides and other biopolymers and particularly as used in subterranean treatment fluids for completion and stimulation of oil and gas wells . advantages of the compositions are the combination into a single package of the properties of clay stabilizing actives and crosslinking actives , in relatively high concentrations , and these compositions are easy to handle , being stable and pumpable at low temperatures , and with attractive environmental profiles . also disclosed are the analogous choline solutions mixed with metallic cross - linking ions know in the art such as zr + , ti 4 + , al 3 + , & amp ; fe 3 + .