Agate is protective, healing and stabilizing. It comes in many colors and varieties, some of those colors represent other properties such as blue lace, moss agate and carnelian. So depending on which kind of you are using, you may want to check those descriptions as well.
All agates do have similarities in which they are all strengthening and grounding. It can also help you connect further with the earth.
It is said to cure insomnia if you place it under your pillow as you sleep, it also works to relieve stress and raise energy.
It can help to ground and stabilize emotions therefore it is helpful sone that feels unstable in the emotional department.