(7) with carb. soda. The alkali is absorbed into the charcoal, leaving an infusable mass which gives the sulfur reaction on silver. (8) Special reactions. If not containing too much iron or manganese gives an alumina reaction with nitrate of of cobalt. In other respects as the preceding. * * * * * Mineral. Turquoise Formula. [...Al=]^{2}[.....P] + 5[.H]. Behavior (1) in glass-bulb. Evolves water, occasionally decrepitates and turns black. (2) in open tube. -- (3) on charcoal. Turns brown, but remains infusible. (4) in forceps. V. As on charcoal. Colors the outer flame green. (5) in borax. In the oxidizing flame, gives a green bead, due to copper and iron. In reducing flame, opaque red. (6) in mic. salt. As in borax. (7) with carb. soda. Intumesces, then fuses to a semi-clear glass colored by iron. With more alkali yields an infusible mass. (8) Special reactions. Gives the phosphoric-acid reaction. * * * * * Mineral. Wavellite Formula. [Al=]F^{3} + 3([...Al=]^{4}[.....P]^{3} + 18[.H].) Behavior (1) in glass-bulb. Evolves water and some fluorine, which attacks the glass. (2) in open tube. -- (3) on charcoal. Exfoliates and turns white. (4) in forceps. V. As on charcoal. Colors the outer flame green, especially if moistened with SO^{3}. (5) in borax. As alumina. Generally gives also a slight iron reaction. (6) in mic. salt. As in borax. (7) with carb. soda. Forms an infusible white mass. (8) Special reactions. With cobalt-solution on charcoal gives the alumina reaction. * * * * * Mineral. Spinel Formula. [.R][...Al=]. Behavior (1) in glass-bulb. -- (2) in open tube. -- (3) on charcoal. -- (4) in forceps. V. (5) in borax. Gives a slight iron reaction. (6) in mic. salt. As in borax. (7) with carb. soda. Fuses partially and forms a porous mass. (8) Special reactions. With nitrate of cobalt gives the alumina reaction. With nitre and carbonate of soda a slight manganese reaction. * * * * * SILICATES.