Heart chakra with it's lovely green colour ( some of us pink) it connects the last three and the first three chakra's together.
This chakra has a big invluence on relations.

When this chakra is weak you have issues with loving and making contact with other people, when you really have a blookge you are scared to make contact with other people. if it is too much open you can have a urge all the time to help people non stop, also you can be a little possesive to other people.
Use green or pink stones to heal this chakra after that you can open or close this chakra a little bit more. The pont is with this chakra is that it is litteraly the centre of the body when this chakra is not working or over working you will feel it in every point of your body, so it is important to take good care for this chakra.