I often refer to this chakra as the stomach chakra but it's true location is at the mass of the small intestine. It is associated with the endocrine system through the pancreas which secretes insulin or glucagon into the blood stream depending on the need for glucose in the body. It is therefore a part of the digestive system as is the small intestine which is where the food the food that we take in is processed and distributed to the cells.
This chakra is a center for processing and orients to our own self-definition with the central issue of power and will. It is our center for vitality, spontaneity and purpose. Our self-esteem lives here. Out "gut" instincts live here as does our ego. We process and act on things in our life from this center. The alter side is that shame also live here.
The element is fire as this is what make a furnace work to process what it is "fed" When this chakra is in excess the person can be dominating, blaming, aggressive and constantly active. A scattered personality exists when this chakra is in excess.
When this chakra is deficient the person will be weak willed, have poor self esteem and be passive, sluggish and fearful. This person may actually obsess on one particular item or thing or thought.
The gemstone most often associated with this chakra is yellow topaz.