The most common paints were red ochre, red lead, soot, calcium carbonate, and other earth colours, which were bound with fat and water. It also appears that the Vikings imported white lead, green malachite and blue azurite from Continental Europe. By using an electron microscope, chemists have been able to analyse traces of colours on runestones, and in one case, they discovered bright red vermilion, which was an imported luxury colour. However, the dominating colours were white and red lead. There are even accounts where runes were reddened with blood as in "Grettis saga", where the Völva Þuríðr cut runes on a tree root and coloured them with her own blood to kill Grettir, and in "Egils saga" where Egill Skallagrímsson cut ale runes on a drinking horn and painted them with his own blood to see if the drink was poisoned.