<P> Allow the bead to cool and the bead is moisturised (traditionally with the tongue) and dipped into the sample to be tested such that only a tiny amount of the substance adheres to the bead . If too much substance is used, the bead will become dark and opaque . The bead and adhering substance is then heated in the lower, reducing, part of the flame, allowed to cool, and the colour observed . It is then heated in the upper, oxidizing, part of the flame, allowed to cool, and the colour observed again . </P> <P> Characteristic coloured beads are produced with salts of copper, iron, chromium, manganese, cobalt and nickel . After the test, the bead is removed by heating it to fusion point, and plunging it into a vessel of water . </P> <Table> <Tr> <Th> Metal </Th> <Th> Oxidizing flame </Th> <Th> Reducing flame </Th> </Tr> <Tr> <Td> Aluminum </Td> <Td> colorless (hot and cold), opaque </Td> <Td> colorless, opaque </Td> </Tr> <Tr> <Td> Antimony </Td> <Td> colorless, yellow or brown (hot) </Td> <Td> gray and opaque </Td> </Tr> <Tr> <Td> Barium </Td> <Td> colorless </Td> <Td> </Td> </Tr> <Tr> <Td> Bismuth </Td> <Td> colorless, yellow or brownish (hot) </Td> <Td> gray and opaque </Td> </Tr> <Tr> <Td> Cadmium </Td> <Td> colorless </Td> <Td> gray and opaque </Td> </Tr> <Tr> <Td> Calcium </Td> <Td> colorless </Td> <Td> </Td> </Tr> <Tr> <Td> Cerium </Td> <Td> red (hot) </Td> <Td> colorless (hot and cold) </Td> </Tr> <Tr> <Td> Copper </Td> <Td> sky blue (hot and cold), opaque </Td> <Td> red, opaque </Td> </Tr> <Tr> <Td> Iron </Td> <Td> yellow (hot and cold), opaque </Td> <Td> bottle - green, opaque </Td> </Tr> <Tr> <Td> Manganese </Td> <Td> pink (hot and cold), opaque </Td> <Td> colorless, opaque </Td> </Tr> <Tr> <Td> Cobalt </Td> <Td> deep blue (hot and cold), opaque </Td> <Td> deep blue, opaque </Td> </Tr> <Tr> <Td> Nickel </Td> <Td> yellow - brown (hot and cold), opaque </Td> <Td> grey, opaque </Td> </Tr> <Tr> <Td> Silver </Td> <Td> colourless (hot and cold), opaque </Td> <Td> grey, opaque </Td> </Tr> <Tr> <Td> Vanadium </Td> <Td> colourless (hot and cold), opaque </Td> <Td> green, opaque </Td> </Tr> <Tr> <Td> Uranium </Td> <Td> yellow - brown (hot and cold), opaque </Td> <Td> green, opaque </Td> </Tr> <Tr> <Td> Chromium </Td> <Td> green (hot and cold), opaque </Td> <Td> green, opaque </Td> </Tr> <Tr> <Td> Platinum </Td> <Td> colourless (hot and cold), opaque </Td> <Td> grey, opaque </Td> </Tr> <Tr> <Td> Gold </Td> <Td> yellow - brown (hot and cold), opaque </Td> <Td> grey, opaque </Td> </Tr> <Tr> <Td> Tin </Td> <Td> colourless (hot and cold), opaque </Td> <Td> colourless, opaque </Td> </Tr> <Tr> <Td> Titanium </Td> <Td> colourless (hot and cold), opaque </Td> <Td> yellow, opaque (hot) violet (cold) </Td> </Tr> <Tr> <Td> Tungsten </Td> <Td> colourless (hot and cold), opaque </Td> <Td> brown, opaque </Td> </Tr> <Tr> <Td> Magnesium </Td> <Td> colourless (hot and cold), opaque </Td> <Td> colourless, opaque </Td> </Tr> <Tr> <Td> Molybdenum </Td> <Td> colourless (hot and cold), opaque </Td> <Td> yellow or brown, opaque </Td> </Tr> <Tr> <Td> Strontium </Td> <Td> colourless (hot and cold), opaque </Td> <Td> colourless, opaque </Td> </Tr> <Tr> <Td> Thorium </Td> <Td> colourless (hot and cold), opaque </Td> <Td> colourless, opaque </Td> </Tr> <Tr> <Td> Yttrium </Td> <Td> colourless (hot and cold), opaque </Td> <Td> colourless, opaque </Td> </Tr> <Tr> <Td> Neodymium </Td> <Td> colourless (hot and cold), opaque </Td> <Td> colourless, opaque </Td> </Tr> <Tr> <Td> Praseodymium </Td> <Td> colourless (hot and cold), opaque </Td> <Td> colourless, opaque </Td> </Tr> <Tr> <Td> Silicon </Td> <Td> colourless (hot and cold), opaque </Td> <Td> colourless, opaque </Td> </Tr> <Tr> <Td> Germanium </Td> <Td> colourless (hot and cold), opaque </Td> <Td> colourless, opaque </Td> </Tr> </Table> <Tr> <Th> Metal </Th> <Th> Oxidizing flame </Th> <Th> Reducing flame </Th> </Tr>

Color of bead in borax bead test is due to
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