Myrrh varies in size from that of a pea to that of a large walnut, and may be even larger. Myrrh is friable and readily powdered in cold weather, but in a warm atmosphere it is difficultly pulverized, unless some of its oil and water have been extracted from it. When heated it softens, then froths up and at length ignites and burns with difficulty. Its proper solvent is rectified spirit. The tincture is transparent, and when poured into water forms a yellow opaque fluid, but does not form a precipitate, while the watery solution is always yellow and opaque.
Alkaline solutions are good solvents for myrrh.
Upon incineration, myrrh leaves about 3.5 per cent of ash, principally calcium carbonate. The volatile oil of myrrh is laevo-rotatory. When exposed to air and light, it resinifies by oxidation and acquires the appearance and consistence of myrrh. Formic acid is said to be developed in this process. Myrrhol , dissolved in carbon disulphide and subsequently treated with bromine or nitric acid, gradually assumes a permanent violet-blue coloration.