This is a natural formation of sodium, and it has the chemical property of NaNO3. This substance is similar, yet different to sodium nitrite, so the two of them should not be confused. Sodium nitrate is a white, crystalline solid that dissolves quickly in water. It does not have an odor, but it does produce a strong, somewhat bitter saline taste when ingested.
The primary use for sodium nitrate is as a food additive. It is generally regarded as safe (GRAS) by both the FDA and the European Union. It acts as a preservative for many cured meats, as well as poultry. Other applications can include fireworks production, where it may be used to replace potassium nitrate. It acts as an oxidizer, helping the black powder ignite faster.
In small quantities, sodium nitrate is harmless to humans, but it may cause mild irritation to the skin or eyes if exposed directly. Ingestion is only harmful if taken in large amounts, and it should not be kept with flammable or combustible materials since it will act as an oxidizer.