Violet relates to self knowledge/ spiritual awareness. It is the union with your higher self, with spirituality, and your higher consciousness.
Violet is the highest colour in the visible spectrum. This colour is known as one of the "cool" colours. It has a very calming effect on us and is, therefore, very helpful for those people experiencing sleep difficulties or stress. However, it can be contra-indicated for those suffering from depressive disorders
Some of the associated problems relating to the crown chakra are Depression, Parkinson's disease, Schizophrenia, Epilepsy, Senile dementia, Alzheimer's , many mental disorders, confusion, dizziness, and even just feeling as if one has a muzzy head.
Violet, being the colour relating to our spiritual connection, can be very helpful for meditation and any spiritual matters.(Violet is used a great deal within religions across the world).