Green powder is made up of the whole stevia leaf. The white powder is the sweetening portion of the stevia leaf removed through a water process and crystallized. This is called stevia extract or concentrate, it can be up to 400 times sweeter than sugar.
The green powder contains more nutrients and phytonutrients and also has a stronger licorice flavouring.
This South American plant has also been called the honeyleaf. Although not approved as a sweetener by the FDA, stevia has been safely used in Japan for the purpose of sweetening for about 25 years. It has only been approved as a food additive in the United States. Stevia products are not standardized, and not all are of the same quality. The pure white powdered extract has the least aftertaste. When using stevia, combine it with at least one other sweetener for better results. Stevia is stable to 400 degrees F, so it holds up well when cooking. However, it will not add texture to baked goods.