Beschrijving
Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Nitratine or nitratite, also known as cubic niter (UK: nitre), soda niter or Chile saltpeter, is a mineral, the naturally occurring form of sodium nitrate, NaNO3. Nitratine crystallizes in the trigonal system, but rarely occurs as well formed crystals. It is isostructural with calcite. The typical form is as coatings of white, grey to yellowish brown masses. It is quite soft and light with a Mohs hardness of 1.5 to 2 and a specific gravity of 2.24 to 2.29. Its refractive indices are n¿=1.330 – 1.336 and n¿=1.580 – 1.587. The rare crystals when found typically have the scalenohedral form of the calcite structure.