Identifying Nickel Minerals

Borax Bead Test. When dissolved in a borax bead in the oxidizing flame, nickel will give it a brownish color. If the bead is heated in the reducing flame for some time, it will become opaque because of the separation in it of metallic nickel. The brown color due to nickel is often masked by the deep blue color due to the presence of cobalt, which is frequently associated with nickel in its occurrence. In this case there is no simple test for nickel.

In Ammoniacal Solution. A comparatively strong acid solution of nickel will on the addition of an excess of ammonium hydroxide become light blue in color. The test should not be confused with the similar but stronger test copper.

Precipitation of Nickel by Dimethylglyoxime. Dissolve the mineral in nitric acid and neutralize with ammonium hydroxide. Filter if necessary. Add a little of a solution of dimethylglyoxime and a scarlet crystalline precipitate forms.