The five-pointed vajra measures twelve units in length. It subdivides into three sections of four units. The central section consists of a central four-unit hub. It has a lotus and moon disc on either side. Sealed at both ends, it has a crown of five extending prongs, each measuring four units in length. The standard unit of measure is the angula or 'finger-width.' This is the distance across the middle finger below the second knuckle. Twelve angulas are equal to one 'face' or large measure. It is the distance in finger-widths from the chin to the hairline. The vajra measures twelve units as it annihilates the twelve links in the chain of causation. Or even the twelve links of dependent origination. Also, the five jina Buddhas are represented by the five pointed vajra.
The Syllable ‘Hum’
At the center of the vajra is a rounded hub. It could also be a flattened sphere. It represents the dharmata as the 'expand or sphere of actual reality.' This sphere or bija seals within the syllable Hum. Its three component sounds represent three things. One is the freedom from causation or karma (Hetu). The second is the freedom from conceptual thought or reasoning (Uha). And the third is the groundlessness of all dharmas (M).
The Lotus Symbolism
On either side of the central hub are three rings. They encircle the lotus bases like bracelets of pearls. These three rings symbolize the spontaneous bliss of Buddha-nature. It is the emptiness, singleness, and effortlessness. Emerging from the three rings on either side are two eight-petalled lotuses. The sixteen petals of the lotuses represent the sixteen modes of emptiness (shunyata). The eight upper lotus petals also represent the eight bodhisattvas. And the eight lower petals represent their eight female consorts. Above the lotus bases are another series of three pearls. They represent the six perfections (paramitas). They are; patience, generosity, discipline, effort, meditation, and wisdom. A full-moon disc crowns each of the lotuses. It symbolizes the full realization of absolute and relative bodhicitta.
The Four Aggregates
Five tapering prongs form a spherical cluster or cross. They emerge from the moon discs. These consist of an axial square central prong and four inward-curving prongs. They unite with the central prong near its tip. The four curved rings are in cardinal directions. They face inwards towards the central prong and have a unique symbolism. There are four aggregates. They are: form, feeling, perception, and motivation. But they depend on the fifth - consciousness.
The Upper Prongs
The five upper prongs of the vajra represent the Five Buddhas. They are Akshobhya, Vairochana, Ratnasambhava, Amitabha, and Amoghasiddhi. And also the unity of their omniscient wisdom, attributes, and qualities. The five lower prongs represent the female consorts of the Five Buddhas. They are Mamaki, Lochana, Vajradhatvishvari, Pandara, and Tara. And also the unity of their qualities and attributes. The Five Buddhas and their consorts have a unique representation. It is that of the elimination of the five aggregates of personality.
The Ten Prongs: Collective Symbolism
The ten prongs together symbolize the ten perfections and the six paramitas. Plus, the perfections of skillful means, aspiration, inner strength, and pure awareness. There are also the ten 'grounds' or progressive levels of realization of a bodhisattva. They go with the ten directions (four cardinal, four intercardinal, zenith, and nadir). Each of the four outer prongs arises from the heads of makaras, which face outwards. The mouths of the makaras are wide open. And the curved arcs of the upper part of the prongs emanate like vajra-tongues from their mouths. The four makaras symbolize the four 'boundless states' or 'immeasurables.' They are compassion, love, sympathetic joy, and equanimity. And also the four doors of liberation. They are emptiness, singleness, wishlessness, and lack of composition.
It also shows the conquest of the four Maras. They are, emotional defilements, passion, death, divine pride, and lust. And the four activities or karmas; the four purified elements; and the four joys. They are joy, supreme joy, the joy of cessation, and innate joy. The tips at either end of the central prong are like a tapering pyramid or four-faceted jewel. It represents Mt Meru as the axial center of both the outer macrocosm and inner microcosm. The twin faces of the symmetrical vajra also represent something. It is the unity of relative and absolute truth.
The Insignia: Crowns of the Five Buddha Family
The above iconographic description reveals the symbolic meanings attributed to the vajra. There follows a description of the vajra as an emblem. A vast number of Vajrayana deities emanate from the mandala principle. It describes the Five Buddha Families as crowned with the 'seal.' The insignia is of their particular Buddha Family. It goes as an image or syllable at the crown of their heads. This derives from the ushnisha or wisdom protuberance on the crown of the Buddha's head. Peaceful deities and bodhisattvas usually bear a small image of their Buddha lord. Or, a small Torana-shaped aureole inscribed with their lord's seed-syllable.
Amitayus has a crown of a small image of Amitabha Buddha or Amitabha's seed-syllable, Hrih. Wrathful forms bear the seal or mark of their particular Buddha lord on their crowns. But usually this takes the form of a half-vajra insignia. Its hub contains the seed-syllable or image of their parent Buddha. The wrathful blue- black deities emanate from Akshobhya Buddha. In their case, the central hub of the half-vajra is actually sealed. And it is, in fact, sealed with Akshobhya's wrathful syllable, Hum.
Beer, R. (1996). The Encyclopedia of Tibetan Symbols and Motifs.