Guaiacwood is a thick, almost solid oil that has to be warmed before it will pour. It smells of roses and smoke over a dry wood base, which is unusual for a wood oil. Guaiol and bulnesol, two heavy woody alcohols, make up most of it and give it that character. Guaiol on its own is a documented natural insecticide.^[1] It is used as a sustainable stand-in for rosewood, and as a fixative that holds a blend together.