Add the baking soda, Epsom salts, cornstarch, citric acid, mica, and eucalyptus leaves to a large bowl and stir with a whisk until completely combined.

Add the sweet almond oil, water, and eucalyptus oil to a small jar, secure the lid, and shake well.

Slowly pour the liquid into the dry mixture, whisking the entire time, so as not to activate the fizz.

Overfill two halves of the bath bomb molds, push together, and gently twist.

Allow bath bombs to set for 8 hours or more, then remove from the mold. You may need to gently tap the bottoms for them to release easier.