by the Mineral Prospector
Prospecting for Minerals and Metals

Flame Test

    Certain elements may be volatilized with a flame test  when minerals containing them are heated intensely before the blowpipe and so impart characteristic colours to the flame.  The flame color to be obtained from a mineral will often serve as an important means of its identification.  A flame test may be made by heating a small fragment of the mineral held in the forceps, but a more decisive test is usually obtained when the fine powder of the mineral is introduced into the Bunsen burner flame on a piece of  fine platinium wire.  The following table gives a list of the important elements which yield flame colors.  It is to be noted that a mineral may contain one of these elements, but because of the nonvolatile  character of the chemical combination will fail to give a flame color.

    Element

    Color of Flame @ Test Time

    Remarks

    Strontium

    Crimson.

    Strontium minerals which give the flame color also give alkaline residues after being heated.

    Lithium.

    Crimson.

    Lithium minerals which give the flame color do not give alkaline residues after being heated.

    Calcium

    Orange

    In the majority of cases a distinct calcium flame will be obtained only after the mineral has been moistened with HCI.

    Sodium

    Intense Yellow

    A very delicate reaction.  The flame should be very strong and persistent to indicate the presence of sodium in the mineral as an essential constituent.

    Barium.

    Yellow green.

    Minerals which give the barium flame also five alkaline residues after ignition.

    Molybdenum.

    Yellow green.

    Obtained from the oxide or sulphide of mo lydenum.

    Baron.

    Yellow green.

    Minerals giving a boron flame rarely give alkaline residues after ignition.

    Copper.

    Emerald –green.

    Azure – blue

    Obtained from the oxide of copper.

    Obtained from the chloride of copper.

    Zinc

    Bluish green.

    Appears usually as bright streaks and threads in the flame.

    Lead.

    Pale azure- blue

    Tinged with green in the outer parts.