Holy oil is made up of either extra virgin olive oil, almond oil or jojoba oil.
To that, you had some drops of a pure essential oil. (And it has to be a pure oil, not synthetic.).
It can be any essential oil that we would deem sacred:
Usually Rose for the Celestial Mother
or Red Sandalwood, Ambergris, Musk, Honeysuckle, Benzoi, Verbena, Vanillin, Myrtle, Patchouli or Calamus.
Usually Frankincense for the Holy Daughter
or White Sandalwood, Camphor, Copal, Jasmine, Eucalyptus, Menthol or Rosemary.
The oil should be poured into a small brown glass bottle with a cap.
Shake the bottle so the oils can mix.
Then, open it back up and trace the Fora over the bottle while saying: May this oil be blessed, in the Name of the Mother, (trace Fora a second time), and of the Daughter, (trace Fora a third time) and of the Great Mother. Blessed is She. Iot ‘E Voh.