atomic number
melting point
660.37 °C

1. Heat the finely powdered infusible mineral sample with a hot flame using a lamp, candle, or Bunsen gas burner, then moisten it with cobalt nitrate solution and reheat it to ignition either on a charcoal block or in a platinum wire loop; the mineral powder will turn blue.

2. Dissolve the powdered mineral sample in an acid solution, then add ammonia to slight excess; a white or colorless flocculent will precipitate; if the flocculent dissolves easily in a basic solution of KOH, it is composed of Al(OH)3 and the presence of aluminum is confirmed.