Bath Bombs with Essential Oils-Homemade Christmas Gift idea

Just got this great Christmas gift idea from a friend. 
My friend Brandi writes: "Hey I made these bath bombs and used DoTerra oils (Serenity and Peppermint), gave them as gifts and were a HUGE hit. Plus I tried them and they feel amazing in the water. I keep thinking that you need a copy of the recipe in case you have a use for it. You may already have something similar but thought I would shoot it over to you just in case. Giving more of them this holiday to my family. :-) "

Thank you Brandi! I decided that we all need a copy of this great idea!  Enjoy :)

Bath Bombs
1 cup Baking Soda
1/2 cup Citric Acid
1/2 cup Corn Starch
1/4 cup Oats, that have been ground in blender (optional)
2 1/2 tbsp Olive Oil
3/4 tbsp Water
1/2 to 1 teaspoon of Essential Oil (Lavender, Peppermint, Frankincense something to promote relaxing with a nice aroma)
1/4 tsp Vitamin E oil (antioxidant which preserves the oils)
1/4 teaspoon Borax (an emulsifier)
Witch Hazel in spray bottle (small amount)
Mix first 3 (and oats if using)  ingredients in medium  bowl until smooth.In separate bowl, whisk olive oil, water, essential oils, vitamin e, and borax until mixture has thickened slightly and is smooth. Drizzle over dry ingredients and mix with your hands thoroughly. Lightly spray mixture with witch hazel 2-3 times. The mixture should start to hold together when pressed in your hand (like fine sand). If it is not, then spray more witch hazel and mix until mixture hold together.
Sprinkle a few oats in the top of molds then firmly press the mixture into the molds. Candy molds work great. You could also use small cupcake tins (do not fill to top) or something you have around the house that works for a "mold". Once complete, allow to harden for 24 hours. This time is needed as if you do not the bath bombs will break apart. This make about 16) 1 1/2 inch bath bombs.