Thanks to Healing Oils of the Bible by David Stewart, Ph. D., I have a better grasp on the construction of oleo-gum-resins. Most of what follows is from his book pp 11-13.

Oleo-gum-resin behaves like the blood of a plant. It circulates the nutrients in conjunction with osmosis. Oleo-gum-resins are usually extracted from a tree by making incisions and letting the OGR bleed out, or by tapping the tree as with maple sap. So in trees, the sap is basically the OGR.

This is the fat-soluble part of the OGR. It is what gets extracted for use in essential oils. Oleo is a very small component of the OGR mixture. In the case of Commiphora Myrrha (myrrh) and Boswellia Carteri (frankincense), the oleo or essential oil is only about 4% to 8% of the raw material. Oleo can be extracted by distillation resulting in an essential oil on one end and hydrosols or essential waters on the other end.

This is the water-soluble part of the OGR. It accounts for the largest part of the raw material at around 60%. Gum can be extracted by soaking or boiling. According to Stewart, “Gums contain the sugar, carbohydrate, amino acid, and protein portions of the plant” (12).

Resin is the alcohol-soluble part of the OGR. Resin accounts for around 35% of the OGR. It can be extracted by soaking in alcohol to make a tincture. Myrrh resin was combined with wine to create a common narcotic use by the Romans. This is what was offered to Jesus on the cross. A great tutorial on making a myrrh tincture can be found here (although eastbae recommends one week, i have seen others recommend at least four).

I plan to investigate the raw OGR, tinctures/resin extracts, and gum waters. I think distilling out oils an hydrosols presents more challenges than i want to deal with at this stage.