Like most green crystals they are heart chakra stones and will help in the area of love relationships as well.
One application where you may use any of the varieties, is to meditate with them, as this may boost your ability to handle life changes.
As they contain quartz this will amplify the energy of the inclusion within them during meditation.
These green stones have a lovely energy that has the capacity to aid you in releasing anxiety, so using them is a good way to relieve your stress.
These crystals are known to also be stones that aid your prosperity. They are known as a stone of luck and will help you to manifest money if that is what you want.
Clear Quartz is known as the "master healer" and will amplify energy and thought, as well as the effect of other crystals.