We are one of the manufacturer and supplier of Perlite Ore. Perlite is a generic name for naturally occurring siliceous or volcanic rock readily available throughout the world.Features: Lightweight Pure whiteness High effectiveness Other details: A unique property of perlite is that it expands up to 20 times its original volume when it is heated to its softening range. This expansion process is caused by the presence of water in the crude rock. When perlite ore is rapidly heated to above 8500??C (16000??F), this water vaporizes and causes the softened rock to expand. Tiny glass-like bubbles are produced which account for the lightweight, pure whiteness and exceptional physical properties of expanded perlite.