nitratine

from the GNU version of the Collaborative International Dictionary of English.

• noun (Min.) A mineral occurring in transparent crystals, usually of a white, sometimes of a reddish gray, or lemon-yellow, color; native sodium nitrate. It is used in making nitric acid and for manure. Called also soda niter.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun mineralogy A trigonal-hexagonal scalenohedral mineral containing nitrogen, oxygen, and sodium.