This summer, I made bath bombs. When I made my bath bombs, I also made soap. My soap and bath bombs had the same smells!
Here are the scents I used in my soap and bath bombs with the colours I used them with:*
vanilla(vanilla is not an actual essential oil, it is a fragrance oil) + lavender - purple
jasmine + rose - pink
vanilla + vetiver - blue
tea tree + eucalyptus - green
*Keep in mind that some of these smells might not work for your preferences. There are so many different combinations to use!
You can use these smells as diffuser blends. If your diffuser can only handle so many drops of essential oil, you can use the same smells but add less drops as a total. If your diffuser needs a lot of drops, then you can make the quantity larger. The recipe I used was the same one as the original bath bombs, and the recipe worked quite well. I did not add any carrier oils.
I made some bath bombs and soaps with these colour combinations. The photos are below.