eEspecially in Kentucky, USA. Available from caves in Virginia and Indiana; Spain Also available in Egypt and India. Ordinary raw yam is usually made from raw materials sourced from Chile, South America. In that country, raw materials are piled high. In some places the floors are up to 10 feet thick, 450 miles long and 5 to 40 miles wide.
It is chemically referred to as sodium nitrate and is chemically abbreviated as Nanda U 3. It is not used for refining because it absorbs water vapor from the atmosphere. However, due to the absorption of water vapor from the atmosphere, the raw material is better used as a fertilizer.