This is popularly known as turmeric oil. Turmeric has three principal extracts, vis--vis, volatile oil (which is the essential oil of turmeric), turmeric oleoresin and curcumin.
The volatile oil in turmeric comprises dturmerones (sesquiterpene ketenes) and 9% tertiary alcohols.
Dried rhizomes yield about 5-6% volatile oil. It is an orangish yellow liquid and has a tuberous odour.
Volatile oil can be obtained through a process of steam distillation of dried rhizome powder or from crushed turmeric tubers.