Reactions of the Green Pigments.
| Pigment. | Hydrochloric Acid. | Caustic Soda. | Ammonium Sulphide. | On Heating. |
|---|---|---|---|---|
| Verdigris (all varieties) | Dissolves to green solution, smell of acetic acid. | Unaltered. | Blackened. | Blackened with evolution of peculiar odour. |
| Bremen green, Brunswick green | Green solution and white residue. | Unaltered. | Blackened. | Blackened. |
| Emerald green, Scheele’s green | Dissolves to greenish solution. | Gradually coloured brownish yellow. | Becomes brownish black. | Blackened and evolve garliclike odour. |
| Copper borate | Dissolves to greenish solution. | Black residue. | Becomes brownish black. | Fuses. |
| Rinmann’s green | Dissolves to rose-red solution. | Unaltered. | Blackened. | Unaltered. |
| Chromium oxide | Almost unaltered. | Unaltered. | Becomes dark dirty green. | Unaltered. |
| Chrome green lake | Becomes deeper in colour. | Unaltered | Becomes dark dirty green. | Unaltered |
| Manganese green | Dissolves to green solution. | Dissolves to green solution. | Discoloured. | Unaltered. |
| Green ultramarine | Is decolourised with evolution of sulphuretted hydrogen. | Unaltered. | Unaltered. | Unaltered. |
On Heating on Charcoal:—Verdigris, Bremen and Brunswick greens give black residues on charcoal, which produce a bluish-green bead when fused with borax in the oxidising flame.
Emerald green and Scheele’s green behave in a similar manner, but on heating evolve an odour of garlic.
Rinmann’s green gives a blue borax bead.
Manganese green is discoloured in the reducing flame.