Granite Gold 24 oz. Sealer, Preserver & Protectant is a water-based formula that is easy to apply and safe for food prep surfaces. It is non-abrasive, non-acidic, and biodegradable in 28 days. This product is safe to use on all natural stone and can be used to reinforce the natural stone's seal and prevent damage and staining. It is recommended to use every 12-18 months. Regularly check the integrity of the seal with an at-home water test. Pour water (about 3 inches in diameter) on the surface in several locations and let it sit for 30 minutes. If you see a dark mark or ring, the water is penetrating the stone and it's time to reseal.