Congealing Point. The congealing point of oil of rose is that degree of temperature at which the first crystals appear when the oil is subjected to slow cooling.
Rose oil consists of 30% stearoptene (the solid phase containing such hydrocarbons as eycosan) and eleopten (the liquid phase). The former is odorless but it fixes the scent well and endues it with durability. When cooler temperatures prevail the stearoptenes present in the oil cause the entire contents of the concum to solidify, but it only requires gentle warmth to cause the Rose Otto to become liquid again.