First, not all natural stone needs protection: if it is only waterproof alkali, in the ten hanging construction some high hardness, high-density stone can not be protected. This condition also applies to some coarse grained granite. For example, in the igneous rocks through the slow-cooling coarse-flowered igneous rocks, large chunks of quartz, the low very dense quartz surface water and other pollutants are not penetrated. The theory has been confirmed and recognized by the American International Stone Association conservation expert Maurizio. Second, the protection of stone materials suitable for the construction of wood, due to the building: in the engineering practice will find the protective agent for some varieties of stone protection effect of poor. To eliminate improper construction and production failure, the most likely reason is not to use the correct stone chemicals for protection. For example, granite and marble because of their mineral composition and chemical composition of different, the formulation of the protective agent is also different. Even the same large type of stone will increase or decrease the concentration of silicone resin because of the different density and chemical composition. For example, the concentration of silicone resin in sandstone protective agent would be higher, and the concentration of silicone resin in granite or marble protective agent with high hardness and density would be lower.