The double vajra (Skt. vishva-vajra; Tib. རྡོ་རྗེ་རྒྱ་གྲམ།, Wyl. rdo rje rgya gram) or crossed vajra is formed from four lotus-mounted vajra-heads that emanate from a central hub towards the four cardinal directions, and symbolizes the principle of absolute stability.
In the cosmographic description of Mount Meru a vast crossed vajra supports and underlies the entire physical universe. Similarly in the representation of the mandala, a vast crossed vajra serves as the immoveable support or foundation of the mandala palace and here the central hub of the vajra is considered to be dark blue in colour with the four heads coloured to represent the four directions-white (East), yellow (South), red (West) and green (North). These also correspond to the five elements and the buddhas of the five families with blue Akshobhya in the centre.
The raised throne upon which masters are seated when teaching is traditionally decorated on the front by a hanging square of brocade displaying the image of a crossed vajra in the centre, often with four small swastikas in the corners. This emblem represents the unshakeable ground or reality of the Buddha’s enlightenment.
- *Robert Beer, The Handbook of Tibetan Buddhist Symbols