Tungsten
W
atomic number
74
melting point
3422°C

1. Mix a small amount of powdered mineral with sodium metaphosphate flux, then apply the blowpipe flame until the mixture forms a molten bead; in the oxidizing portion of the flame, the fused bead is colorless both hot and cold; in the reducing portion of the flame, the fused bead is green in color but turns a beautiful blue when it cools.

2. Mix a small amount of powdered mineral with some sodium carbonate flux, then apply the blowpipe flame until the mixture forms a red-hot bead on the end of a platinum wire loop, next grind up the cooled bead into a powder and add it to a solution of hydrochloric acid, finally add a small strip of metallic zinc and then boil the mixture until the powder dissolves; the solution will turn a fine blue.

3. Place a small amount of finely powdered mineral on a piece of aluminum foil, then add a droplet of dilute HCl to the powder; tungsten-bearing compounds will eventually impart a blue color to the solution if it is left standing.