Natural pigments obtained from natural earth and ochres are extracted from quarries. These non-toxic pigments yield soft natural tones with a matte opaque finish and are UV resistant. Our small packets of pigments are sold by volume (only the larger 1 kilo/2.2 pound bags are by weight). The values indicated on the labels (ex: 80ml/2.7 OZ or 150ml/5 OZ) are volume, not weight. As every pigment has very different densities and as we use volumes of pigments for our paint recipes, we sell the smaller packages in volumes to align with our recipes.