Kind of rubber is a broad term that can refer to a variety of materials. India rubber, also known as caoutchouc, is a natural rubber made from the latex of certain trees. Silicone rubber is a synthetic rubber made from silicone polymers. FOAM rubber is a type of open-cell FOAM made from latex or synthetic rubber. Crepe rubber is a type of rubber made from latex that has been treated with sulfuric acid to give it a crinkled texture. Para rubber is a type of rubber made from latex that has been treated with formaldehyde. Ceara rubber is a type of rubber made from latex that has been treated with ammonia.