Sulphur Black 1:Sulphide black can be divided into BR (bluish red) and B (bluish blue) according to different colors. The color and quality can be adjusted according to customer requirements. Appearance: shiny black flakes or granules Product properties: sulfide black is insoluble in water or ethanol, green black in sodium sulfide solution, blue when caustic soda is put into sulfide black solution, and green precipitate when hydrochloric acid is used. The product is slightly soluble in cold sulfuric acid, and turns green and blue after heating. It turns black and blue when heating continuously. Sulfide dyes have good dye uptake and levelness.