Vert de Gris: the originality of the color is based on both gray and green tones. From the corrosion of copper, greyish combines with both light and dark colors for a rendering of both soft and deep writing. 35 beautiful colors! Non toxic and pH neutral Water based Flows smoothly and is fast drying All natural dyes *Go see in the 'Specifications' section below the PDF file to have a look at the inks colors.