A precipitated silica having an SiOHisolated absorbance ratio of greater than or equal to 1.5, a silanol group density of 1 to 3.0 SiOH/nm2, a modified tapped density of 1 to 50 g/l, and a pH of 3-5, when measured as a aqueous suspension of 5.00 g of the precipitated silica in 100 ml. of deionized water allows preparation of storage-stable RTV-1 silicone rubber formulations without stabilizer. A process for preparing the precipitated silica and its use in thickening sealants is provided.