The Sand Mandala is regarded within Tibetan Buddhism as sacred and, until 40 years ago, was rarely seen outside the monasteries. Architectural in structure, their complex and richly coloured designs have remained unchanged for over 500 years, the skills and secret meanings passed faithfully down through the generations from teacher to student.
The mandala is, in essence, a visualization tool, a symbol of a perfect world in which we are all perfect beings practicing the pure loving kindness and compassion that is innate in all living beings. Visualizing oneself in the center of this perfect world of the mandala creates the conditions for us to behave towards others with kindness and compassion, which in turn, causes them to develop a similar outlook and leads to the creation of such a perfect world.
Mandala '. all who see it will be blessed'.
http://www.gyuto.va.com.au/gyuto/monks/ritual/mandalas.html
According to Buddhist scripture, sand mandalas transmit positive energies to the environment and to the people who view them. While constructing a mandala, Buddhist monks chant and meditate to invoke the divine energies of the deities residing within the mandala. The monks then ask for the deities' healing blessings. A mandala's healing power extends to the whole world even before it is swept up and dispersed into flowing water a further expression of sharing the mandala's blessings with all.
The Tibetan mandala is a tool for gaining wisdom and compassion and generally is depicted as a tightly balanced, geometric composition wherein deities reside. The principal deity is housed in the centre. The mandala serves as a tool for guiding individuals along the path to enlightenment. Monks meditate upon the mandala, imagining it as a three-dimensional palace. The deities who reside in the palace embody philosophical views and serve as role models. The mandala's purpose is to help transform ordinary minds into enlightened ones.
http://www.asia.si.edu/exhibitions/online/mandala/mandala.htm
The word “mandala” stems from Sanskrit, the classical language of India and of Hinduism, and means “circle”. We see mandalas everywhere in life. The iris of the human eye is a mandala. Think of the wheel, the face of the clock. When we look at nature, we see the most beautiful mandalas in the rosettes of flowers. Healing takes effect in multiple ways through the use of these special manadalas. Not only are they healing on a physical-level but also on the plane of the emotions, as they have a strong effect on our feelings /what’s more they have a uniquely powerful effect on the spirit, and are thus able to heal spirtitual wounds.
Mandalas for Healing: by W. Mertl & H. Janko