Blockx Chrome Green 15ml Watercolor Tube Chrome green no262, also known as chromium oxide green, is opaque and popular for landscapes Blockx watercolor is made in belgium since 1865 by the blockx family, 5 generations of chemists. Highest quality pure pigments ensure maximum color strength and quality. Rare, tough pigments are thoroughly crushed, then coated in gum arabic and honey. Blockx has no hues, tints, fillers or transient or unstable (non lightfast) colors, such as alizarin crimson for example