Place baking soda, sea salt, clay, rose hip extract/colorant, rose hip seed oil, and lecithin into the mixing bowl. Whisk the mixture to blend in the color and remove any clumps of baking soda. Whisk until it is of uniform fine consistency and a pale pink in colour.
Using the whisk, stir in the essential oils. Mix well so that the mixture has a uniform consistency.
Whisk the citric acid into the mixture. There is no water in this mixture so there should be no foaming up. Mix fully with the whisk.
There is no need to treat the molds. The mixture will drop out of the molds without issue.
Working in a well-ventilated area, spritz the mixture lightly with the alcohol, while whisking to prevent a fizzing reaction. Avoid breathing in the alcohol. Add only enough alcohol to allow the mixture to clump together when squeezed in your hand. It should have the moisture content of barely damp sand. Try three spritzes and then check the consistency. Test it to see if it will hold together. It should be fluffy after spritzing, not dense and wet.
Only add more alcohol if the mixture won’t hold together easily. How much alcohol you need depends on the relative humidity in your air.
Using the bath bomb mold, scoop up enough of the mixture into each half of the bath bomb, so that both sides are over-full. Really pack it in. Press the two halves of the mold together tightly, to compress the bath bomb mixture into a tight package. Brush off any excess mixture.
Allow the mold to sit undisturbed for 10 to 15 minutes. Tap the outside of the mold on both sides with the back of a spoon to loosen the bath bomb. Open the mold and pop out the bath bomb onto a piece of parchment paper-lined baking sheet. Be gentle. The bath bomb will solidify as it dries.
Allow the bath bombs to dry overnight. Turn it over and dry for an additional 12 hours. Wrap the bath bombs in plastic wrap or a shrink wrap, if desired, to make them more secure if you are gifting them.