=Emerald Green.=—This pigment must not be confounded with the more important copper compound previously described, to which the name emerald green is usually applied. It consists of chromium hydroxide obtained by precipitating a solution of the green modification of a chromium salt by zinc hydroxide. After careful washing it has a dull green shade; it is a very durable pigment. =Chrome Green Lake= is a mixture of chromium oxide with alumina; it is obtained by precipitating a solution of alum and a chromium salt by a soda solution. The precipitate, which contains aluminium and chromium hydroxides, on ignition takes a paler shade in proportion to the quantity of alumina it contains. For the chromium salt a solution of potassium bichromate, which has been allowed to stand with sulphuric acid and alcohol until if has acquired a pure green colour, may be used. =Turkish Green.=—This pigment, which retains its fine green colour in artificial light, is prepared in a peculiar manner: 40 parts of alumina free from iron, 30 parts of cobalt carbonate and 20 parts of chromium oxide are thoroughly ground in a mortar. The mixture is placed in a porcelain tube, which is exposed to a strong white heat whilst pure oxygen is led through. The oxygen may be replaced by air if it is previously heated and under pressure. Another recipe for Turkish green is to intimately mix 4 parts of freshly precipitated alumina with 3 parts of cobalt carbonate and 2 parts of chromium oxide, heat the mixture in a crucible at a white heat, powder and levigate. Turkish green has a characteristic bluish-green colour; the shade is inclined to blue or green by increasing the quantity of cobalt carbonate or chromium oxide. =Leaf Green= is a pale green, very durable pigment similar to chrome green lake. It is obtained by igniting mixtures of chromium oxide with pure aluminium hydrate; the paleness of the shade is in proportion to the amount of alumina. =Chromium Phosphate Pigments.=—Several chromium phosphates are used as pigments; the more important are described here. =Arnaudan’s Green= is chromium metaphosphate; it is obtained by intimately mixing 128 parts of neutral ammonium phosphate with 149 parts of potassium bichromate by long grinding, and carefully heating the mixture at 170° to 180° C., but not higher, until the mass is pure green. It is then brought into hot water and thoroughly washed; it has a very handsome green colour, which is not altered in artificial light. Ammonium arsenate may be used in the place of ammonium phosphate; a handsomer green is then obtained, which is, however, very poisonous.