Once upon a time you could not pick up a mineralogy book without coming upon a whole battery of tests to help identify your mineral. But today these useful techniques which include fusibility, flame colour, blowpipe tests, bead tests and tube tests have all but dissapeared from texts. Instead these valuable hands-on techniques are largely forgotten in favour of observational non-participative methods like streak, hardness, colour and crystal form.

To some degree we can understand this shift when considered in our health and safety concious world. Some of these tests involve the use of chemicals and heat. Also new new spectrospic and crystallographic methods have arisen, whose accuracy have made the older methods appear obsolete.

However, we believe the veteran methods are valuable for two reasons. First, the new lab-based techniques are beyond the means of most collectors. And second, with due care and attention the tests can be perfomed in safety and with little personal danger. Yet they provide remarkably accurate confrimation of a mineral`s composition. So the evidence continues to speak in their favour.

Flame Test

This is the easiest of the tests and involves the heating of a mineral sample in a flame. The colour of the flame will change according to the principal chemical content. Thus, for example copper will turn the flame green and potassium violet.

Charcoal Test

This involves blowing a stream of air and flame onto a mineral sample backed by a block of charcoal. The nature, position, colour and smell of the residue that forms on the block are key indicators of the elements present.

Blowpipe Test

This is a more complex version of the flame test whereby a stream of air is blown into a flame through a mouth-held blowpipe. The airflow produces two regions within the flame, one with a reducing, and one with an oxidising properties. Placing a sample in one of the regions will often produce a small button of the main metal. Some like gold and copper are easily identified whereas others may need further analysis.

Bead Test

This is an extension of the blowpipe test whereby small amounts of the mineral specimen are dissolved a chemical bead. This is prepared beforehand by heating a platinum wire loop in a flame and dipping into one of several different chemical fluxes. Those most commonly used include borax or a phosphate. Depending on which part of the flame the mineral and flux is then heated, the bead will cool to a different colour. Thus copper in a phosphate flux will produce a blue bead in an oxidising flame and a red one in the reducing part.

TubeTest

This group of tests involve heating the mineral sample in a glass tube, usually alone but sometimes in the presence of sodium carbonate, charcoal or magnesium. The identification is made according to what happens. For example some elements will form different coloured sublimates at the cool end of the tube. In other situations steam may be produced indicating the presence of water.